It’s been a big factor in Linux now having extremely strong support for windows games, as it runs Steam on Linux and uses PC hardware to play PC games, and it’s built/supported by Valve who did a lot of the heavy lifting on improving the existing Linux windows compatibility layer to where it is now. What that means for you is basically anything in Steam will run well in Linux even if it’s not a native Linux game (which most aren’t).

Otherwise, Proton’s the name of Valve/Steam’s compatibility layer project, and you can look up game-specific user reports on playability here: https://www.protondb.com/