Price and Soap are both gonna be in it. So will Nikolai, and Makarov will be the primary bad guy.
As far as I know there are four playable characters:
Derek "Frost" Westbrook and Sandman, two Delta Force Ops in NYC (The other two NPCs in their squad are named Truck and Grunt)
Marcus Burns, an SAS Sgt. in London
Yuri, a Russian federal agent