Thankfully, Modern Warfare 2 does have split-screen capability, meaning you can play co-op with friends. However, you'll only be able to use it in Private Matches within the Multiplayer mode. Note that it also only supports two players rather than the classic four-player split-screen.
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.