Call of Duty is currently in the hands of Treyarch, who previously worked on the third game and are taking the first person shooter back to WWII with the forthcoming World at War. There's still no news on where the next game will be set, and though Infinity Ward is thought to be at work on a futuristic science fiction shooter, it's more likely that this is the touted new IP for the company rather than the introduction of ray guns to the series.