Pretty sure that Naughty Dog is developing The Last of Us 2. But they are also working on a new IP.
Same thing with Sucker Punch. They are working on a new InFamous project and on a new IP.
Santa Monica is probably working on Playstation All-Stars: Battle Royale 2 next to God of War PS4 and Guerialla Cambridge is probably working on a new Killzone game next to RIGS.