Multiplayer in Call of Duty: Ghosts will introduce the "Squad", a group of up to 10 soldiers with unique loadouts and appearances, with one level of prestige per character. These guys will also join you, as AI teammates -- or adversaries -- in a new mode called, of course, Squads.
This video does all of the explaining, but the feature sounds really cool. Their behaviour will change based on the loadout they're given too. Fighting in Squads will earn you XP the same as any other multiplayer mode too.