While the upgrade from 50D to 7D Mark II would be good for wildlife photography, it would be less so for landscape photography.
Very generally speaking, for wildlife photography an ideal camera optimizes working with telephoto lenses.... an APS-C cropper like 50D and 7DII is great because that "leverages" lens focal length. The best camera for the purpose also has a high performance AF system that's both quick to acquire and good at tracking moving subjects. High frame rates can be handy, too. Sports, and to a lesser degree wildlife photography, doesn't typically demand high resolution. Many of the "top" performing sports cameras are 20, 21 or 24MP.
It's largely the opposite with landscape photography. The "best" camera optimizes working with wide angle lenses... a full frame or even medium format camera may be the most ideal, but also ends up being bigger, heavier and more expensive. This isn't to say that landscape photography is only done with wide angle lenses. Just that there is a bias toward shorter focal lengths, where for sports and wildlife the opposite is the case... there is a bias toward using powerful telephotos. AF performance doesn't need to be particularly rapid or good at tracking for landscape photography. It just needs to be accurate. And fast frame rates are rarely used for this type of photography. In fact, longer individual exposures are more likely. On the other hand, high resolution and good capture of fine detail can be important factors for landscape photography.
The "best" camera for you needs to be a compromise that does the best job addressing both these types of photography, which can be at odds with each other.
Even though I use a pair of 7D Mark II myself (mostly for sports... also for some wildlife), it's not what I'm going to recommend.
The best camera for you would be the Canon 90D. Here's my reasoning...
On the one hand, 90D is a crop sensor camera (like 50D and 7DII). And it has frame rates that largely match the 7DII's. 90D also has a reasonably high performance AF system quite capable of handling most sports & wildlife situations (although I still think the 7DII's AF system is superior by a small margin). The 45-point AF of the 90D will be a big step up from the 9-point AF in your 50D (three of which I used previously for a lot of sports, and some wildlife... before moving to a pair the original 7D for five years... then to a pair of 7DII a few years ago).
90D also has very high resolution for an APS-C camera, making it very usable for landscape photography. I won't kid you, a full frame camera might be even better capturing fine detail and at high ISOs... but not by a huge margin. The 90D offers 32.5MP resolution in a crop sensor body (so does the mirrorless M6 Mark II, by the way). This is higher resolution than most Canon full frame cameras! Full frame Canon 5D Mark IV and EOS R are both 30MP... full frame 6D Mark II and EOS RP are both 26MP. Right now only the 5DS and 5DS-R offer higher resolution: 50MP. The EOS R5 coming this Summer hasn't been specified, but many believe will be a 45MP camera. Sometime later, maybe next year, Canon is expected to produce an even higher resolution full frame model... probably in the 70MP to 85MP range. (Scaling up 32.5MP from Canon APS-C to full frame would make for an 83MP sensor... so that's what I'm betting on.)
Look online for reviews of 90D, image testing and examples. It's pretty impressive, considering that 32.5MP is the most of any APS-C camera being made by anyone today. It's also a big bump up from your 50D's 15MP or the 7DII's 20MP. Heck, it's even a big increase compared to the 24MP 80D.
The 90D also has Canon's Dual Pixel Live View AF and an articulated rear LCD Touch screen... both of which might be handy for some situations you encounter (and the 7DII lacks, as does your 50D).
There are a few ways that 7DII might be the "better" camera, but I doubt they will be of much concern to you. 7DII is more robust and rated for higher durability. It uses a lot of magnesium outer panels, where the 90D uses more high impact plastic. The 7DII also has slightly more sealing for weather and dust resistance, though the 90D is pretty good in this regard too (better than my two 30D that I soaked in a downpour some years ago, but was able to dry out and continue using!) The 7DII's shutter is rated to give 200,000 actuations, while the 90D's is rated for 120,000 clicks. For comparison, your 50D's is rated for 100,000... but you must not be an extremely high volume shooter, if you've worked with a 50D for this long.
The 7DII also has a slightly better optical viewfinder... both it and 90D have 100% coverage of the image area, but the 7DII gives a wee higher magnification... 1.0X (image in viewfinder is same size as when viewed directly with your eye). The 90D comes very close though, with something like 0.97X or 0.98X magnification. The difference should be hardly noticeable. The 7DII's 65-point AF system, all higher performance "cross type", is highly configurable and customizable, with seven different AF "patterns"... and a separate, 50 page user manual to describe all the adjustments and tweaks you can make. But the 90D comes close in this respect, too... it's 45-point AF system is also all the higher performance "cross type", and it has five different AF patterns to choose among, as well as a lot of user customizability.
The 7DII's AF performance is partly due to using a discrete chip to run the AF, while it's dual Digic 6 processors handle image processing and other functions separately. This arrangement has only been used in original 7D and 1D/1DX-series cameras. 90D uses a single processor for everything, but it's a two generation newer Digic 8, which saw a big jump in performance compared to earlier Digic processors. Digic 8 cameras are the first Canon capable of shooting 4K video, too. Digic 7 and earlier were limited to HD at most. If I recall correctly, compared to HD, 4K video means more than double as much data has to be handled by the processor, so the 90D's Digic 8 must be a lot more powerful than previous processors. (By the way, the 80D used a single Digic 6 processor for everything, and it's no slouch, though it maxed out with HD video.)
In one respect, 90D's (and 80D's) AF is superior to 7DII's. Your 50D
is not "f/8 capable". This means the max lens aperture that allows it's AF to work is f/5.6. So, for example, while a Canon EF 400mm f/5.6L USM lens will autofocus fine on your camera, if you attach a 1.4X teleconverter to the lens, the camera's AF will no longer function. These newer cameras
are "f/8 capable". The 7DII has a single AF point at the center (out of 65 total) that will work when a 1.4X TC is added to an f/5.6 lens or when a 2X TC is added to an f/4 lens. However, with select lens/teleconverter combos the 80D and now the 90D are able to autofocus with more of their 45 AF points... up to 27 of those points are "f/8 capable". This varies a lot depending upon the exact lens and TC, though. For example, the only combo I know of that allows using any of 27 points is the Canon EF 100-400mm L "II" with the Canon EF 1.4X "III" TC. Some other lens/TC pairings allow multiple points, but not this many. And a lot of combos are restricted to the center point only, same as 7DII.
7DII has dual memory card slots (one Compact Flash, the other SD). 90D has a single slot: SD (which supports faster UHS-II cards, while the 7DII's supports UHS-I).
7DII layout, controls, ergonomics and general "feel" are somewhat more similar to 50D. While the 50D was Canon's top-of-the-line APS-C model in its day, they sort of split that category in two with the 60D and original 7D that followed (both 18MP). It's arguable the 7D series was developed and added to the Canon line-up because Nikon had introduced the D200 and then D300, which were more pro-oriented APS-C models. In some respects Canon sort of "cheapened" the 60D compared to the 50D that preceded it, at the same time they "upgraded" the original 7D. But a lot has happened since then... 70D inherited the 7D's 18MP sensor, but the 70D makes better use of it, producing sharper images. 70D also introduced a new feature called Flicker Free or Anti-Flicker, which is very effective solving exposure problems under fluorescent and similar lighting. (7DII, 80D and 90D have it too, as do most Canon DSLRs and MILC now.)
70D also was the first model to get Dual Pixel AF in Live View. DPAF uses pairs of sensors embedded directly in the image sensor to autofocus. This greatly improves AF in Live View and now is found in nearly all Canon DSLRs. It's also the AF system used in all Canon mirrorless models since the M5 and M6 (2016/2017). 70D also got the Canon Micro Focus Adjustment feature re-instated. Your 50D has that. For some reason, Canon left it out of the 60D, though they put it in the 7D. Thankfully, they put it back in the 70D and nearly all subsequent models.
But, 7D Mark II is closing in on six years old, while the 90D is less than 1 year old. Canon introduced the 90D as a replacement for both 80D and 7DII... However while the 90D has clearly superseded 80D and is a solid update and upgrade from that model, a lot of 7DII users don't consider it a direct replacement and there is a good deal of speculation (hope?) that Canon will eventually produce a 7D Mark III model. Canon marketing seems to have pivoted away from the idea that 90D replaces both the preceding models, too.
So, while 7DII remains a top pick for pros doing high volume sports photography.... for someone like yourself, especially with your interest in landscape photography too, the 90D is very likely a better choice. Even if Canon gets around to making a 7D Mark III, it may get some incremental upgrades but is likely to be no more than 24MP and the 90D will still be better for some purposes or mix of purposes... like yours.
Best of all... 90D costs less. Even now when 7DII's "street price" has dropped quite a bit from when it was introduced and it's on sale with a $250 discount.... 7DII still costs $1399. That's $200 more than the list and current $1199 price of 90D!
The price difference carries over into some accessories, too. The BG-E16 battery grip used by the 7DII sells for $209... while the BG-E14 that the 70D, 80D, 90D all have used is selling for $169. Granted, the 7DII's grip has some add'l control features (a secondary "joystick" and AF pattern toggle switch), which the BG-E14 doesn't have. But, a grip may not be needed on it because the 90D is also a more power efficient camera. Using the same LP-EN battery the 90D is rated to get almost double the number of shots per battery charge as 7DII. Standard testing says 90D should get around 1300 shots, where 7DII gets 670 (both using CIPA testing standards... most users get significantly higher number of shots with various power saving techniques).
Some 90D vs 7DII comparisons:
https://cameradecision.com/compare/Canon-EOS-90D-vs-Canon-EOS-7D-Mark-IIhttps://www.imaging-resource.com/cameras/canon/7d-mark-ii/vs/canon/90d/https://www.digitalcameraworld.com/news/canon-eos-90d-vs-eos-80d-vs-eos-7d-mark-ii-12-key-differences-to-be-aware-ofhttps://www.the-digital-picture.com/Reviews/Camera-Specifications.aspx?Camera=1443&CameraComp=963I also recommend reading some of the in depth reviews of both cameras you'll find online... Bryan Carnathan specializes in Canon gear and his reviews are always a good starting point:
https://www.the-digital-picture.com/Reviews/Canon-EOS-90D.aspxhttps://www.the-digital-picture.com/Reviews/Canon-EOS-7D-Mark-II.aspxIn my opinion, the most ideal Canon camera for you is the 90D... It simply does the best job meeting your somewhat disparate purposes. And it would be a super upgrade from your 50D, at lower cost than 7DII. That's my recommendation, even though I use a pair of 7DII myself (though my uses for them are more sports/wildlife... AND I have full frame for the occasional landscape and some other purposes).
While the upgrade from 50D to 7D Mark II would be ... (
