How People With Different Types of Colour Blindness See the World

I've always wanted to ask: How do special color blind modes (eg in video games or mobile phones) help colorblind people? Do they help you see things in all colors or doesn't it matter, since you're only able to see 'specific' colors?

Color blind filters help a lot in certain games it really depends on the game though, part of the reason I've quit overwatch is because their color blind mode is horrible.

I don't remember if Splatoon has it, but there is a "Color Lock" option in Splatoon 2 for the Switch. I haven't looked at it yet or looked online about it.