Why do people keep mentioning Cronus and XIM in here as if it's comparable? You can use KB/M in Warzone by default on any platform if you like, just like you can use controller on PC
Cronus will let you use a mouse/keyboard, yes, but it can also run scripts that can allow you to do god-like stuff with a controller that you wouldn't normally be able to do. The two get conflated too much, I agree.