Local co-op in PC with keyboard & controller at the same time

Im trying to play with my son in PC but we only have 1 generic controller and the keyboard. The problem is when we try to enter campaign with split screen the controller isnt recognized as a 2nd player so the Game Launches error asking for a 2nd controller. Ive tried connecting the controller after the Game is launched, also running it from steam big picture but nothing works. I would be very Happy if someone could give me some help.

What controller?

Normally I download drivers for the Xbox One controller I plug in :+1: