Call of duty 5 is going to be the fifth addition to the Call of Duty series, or 8 if you include all the current expansion packs and any console versions.
The news of this new addition was confirmed on December 2, 2007. The expexted release date is sometime around March 31 2009 which is the end of Activision's fiscal year. The game will be available on the following platforms: XBOX 360, Wii, Playstation 3, Playstation 2 and PC.

Treyarch are indeed hard at work on Call of Duty 5. And that, yes, the series is heading back to World War II. That's the stuff we'd heard already. What we didn't know is that, according to this tipster, the game's set in the under-utilized Pacific theater, something only one major WWII shooter - the awful Medal of Honour: Pacific Assault - has tried before. While (if true) the move back to well-worn WWII is mostly disappointing, if this game can branch out and explore some of the less "popular" aspects of the conflict (China, Burma, New Guinea), it might not be so bad.