playing co-op (split screen) with son on second controller on Xbox series x

Hi there Magdestroyer welcome to the community forum! Christopher here, an Xbox fan just like you and has been on Xbox for years already. I would really love to make your day by helping you out. Yes of course! You just need to investigate if the game has splitscreen!

support for split screen is not universal with games however dual controllers will enable the mode in supported games

having said that in the old days when consoles were not as available I recall playing quake II in a quad split screen with an ancient PS2

even games on the PC occasionally feature split screen

If you have a second controller, you could sign in co-op split screen and throw it at your guest.

Goldeneye Reloaded has local split-screen (unfortunately, no co-op), I'd recommend ignoring the "M" rating associated with Halo 3 (why it's rated as such is beyond me) for it has fantastic split-screen co-op and custom games, play it with my own son regularly...

Will probably pick this up when I get a second controller (so basically when they release Xbox One in Finland) mostly for couch co-op with friends unless there's something else with split screen co-op out by then