A CPL or Circular Polarizing "filter", unlike coloured or tinted filters, does not change the colour or colour intensity or saturation of any given scene as to specific to colour or subject. Coloured filters will shift the colour of the entire scene or subject. They will warm or cool everything in the frame. As an example an 81-A or mild warming filter may enhance the warm tones of Autumn foliage- at the same time, it may kinda desaturate the blue colour of the sky. What's more, coloured filters will not cut through the reflections that cause colour desaturation.
Technically speaking, a CPL "filter" is not a FILTER in the conventional sense, as it does not hold back (absorb) or intensify or emphasize (transmit) any given colour or proportion of that colour. CPL filters are neutral in colour.
A polarizing "filter" enables the photographer to control or eliminate certain reflections from the surfaces of various objects. On a bright sunny day and many other natural light conditions, where the angle and incidents are at a certain position to the camera, the surface reflections off of the foliage and other surfaces tend to gray down, desaturate or negate the vibrance of the rich colour we have come to expect under certain lightg conditions. So, by employing a CPL filter, the rich reds, yellows, greens and subtle browns we associate with the Fall season will be rendered better. At certin angles, the blue sky and contrast with clouds will intensify as well.
A high-quality CPL filter is a great accessory to have in your toolbox for many other applications as well as landscape and skyscape work. It can enable you to shoot through glass and Plexiglass in storefront windows aquariums, museum dioramas, shooting for enclosing observation decks where you can not open a window- all without most of the distracting reflections. The CPL filter is a necessity for photographic paintings, flat artwork and many kinds of documents. In combination with polarized light sources, it can eliminate all unwanted reflections in non-metallic objects.
You are in control- by rotating the filter you can previsualize and determine the extent of the effect you want to achieve. There are certain reflections in water or windows that you may not want to negate in certain scenes so you will need to compromise as to how much of the effect you want to employ.
Beach CPL filters have intrinsic neutral density you will lose around 2 f/stops. With most kids of landscape work, this is not problematic because you can select an aperture to provide adequate depth of field and lens performance, ad compensate with a slower shutter speed and tripod usage. On a bright sunny day, you may still be able to handhold the camera without issue- even at a low to moderate ISO setting.
How do polarizing filters work? Here is a good article without too much complex science:
https://www.shutterbug.com/content/how-polarizing-filters-work-and-why-you-should-use-one-your-dslr-camera