Yes, Call of Duty: Modern Warfare 3 has full cross-platform support. This means that you can squad up with players on any console PlayStation, Xbox, or PC and enter the battlefield together. This is true for any online mode in the game.
PlayStation 4 players can jump into Special Ops: Survival, an exclusive* wave-based horde mode. And each Modern Warfare season will bring a new location to Survival, as well as a special Challenge Mission and reward for other game modes.