Well... It is called wine!
Edit: in response to ekianjo below, I can't reply: Thank you, I wasn't aware of that. I thought it was coupled with Steam tightly. I have even found a Gentoo overlay with a Proton ebuild. I'll give it a spin; I'm not a huge fan of the Linux desktop but I'm tired of Windows 10 chapping my hide with its endless stream of background processes consuming the resources of my computer while I'm trying to do something else.
I've not had much success with WINE for gaming, nor with Proton. I used to play some "Tom Clancy" games using WINE (Origin, I think it was; bought a couple of other games Rayman and something else) but the distributor changed the launcher and it never worked again. I couldn't for the life of me work out why they didn't advertise the fact their launcher worked on WINE, v. simply, nor why they would then squander that advantage by breaking that compatibility (some update loop, apparently it could be worked around but my WINE-fu wasn't up to the task).