I have been waiting for ray tracing on my favorite CoD since the first RTX remix demo! To think it's coming to this is amazing! I wonder if it will be done to other CoDs.
It's not any game, it's only games on D3D9 and before, and those games must have a fixed rendering pipeline. This means we are limited to games that are at least 15 years old as of now. Maybe in the future through updates we will be able to apply it to more modern games but as of right now the compatibility is very limited and even in WaW and CoD4 people are having trouble getting it to be stable enough to actually be worth releasing.