Setting up Split-screen\n\n Players can now start MW2, and once they reach the main menu, the second player should press the prompted button to join the game (X for PlayStation, A for Xbox, or Space for K/M). At this point, the second player must either log into their Activision ID profile or play without one.

So you playing with a mouse against someone on the phone is kinda cheating but don't worry. Can mobile COD players play with console players? No. Only PlayStation, Xbox and PC players can cross play.

As the title suggests, Call of Duty: Warzone Mobile is a mobile-exclusive game with no crossplay features. Players can only team up with and compete against other mobile users. Essentially, WM will have dedicated servers separate from PC, PS5, PS4, Xbox One, and Xbox Series X/S versions.