It's not on GamePass and it doesn't need Xbox Live Gold either. MW2 and its multiplayer component is not free. You need to buy it if you want to play the single player game or MW2 multiplayer. You should be able to delete the campaign if you don't want to buy it.

If you will be playing the game campaign for the game no need for an Xbox Live Gold, you just need to set your console to offline. To do so please follow the steps below: Settings > General > Network Settings > Go Offline.

PICO-8's controller support is based on the SDL library. A game can have up to 8 simultaneous players. Players 1 and 2 can use game controllers or corresponding keys on the keyboard.

Flexible levels\n\n Each level adjusts its terrain for the total number of players, so you can enjoy these to the fullest whether you have many friends or just one.