Multiplayer in Call of Duty: Ghosts will introduce the "Squad," a group of up to ten 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 behavior 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.