One of the surprises during the Summer Game Fest Kickoff Live was an announcement of a brand new developer called Deviation Games. It is founded by two Treyarch veterans - Dave Anthony and Jason Blundell - who previously have worked on the Call of Duty series.
While they did not want to tell anyone what they are working on, they did however reveal that it is a AAA PlayStation exclusive. In a lengthier post on the PlayStation Blog, they also explained that "we're over 100 Deviators and growing fast" and that they "can confirm development is already underway".
Considering the founders Treyarch background, we would assume it's multiplayer related, but this is of course purely speculation on our behalf.