What we know
Well there's precious little information actually available about the next Call of Duty game, with the usual tactics of publisher Activision being to hold the new game under heavy wraps as the downloadable content for the current one is being delivered, with a big reveal probably coming at some point during E3.
Speculation from various sources suggests that there are at least two
Call of Duty branded titles developed, one worked on by Treyarch, the people who also delivered Black Ops, and the other linked to newly formed Sledgehammer Games.
There's also information about Infinity Ward being back in the development process, perhaps with some assistance from Raven.
The rumors also suggest that the franchise might be pushing forward, taking gamers into space in a near future adventure, while other sources are claiming that the next game to arrive will be based on the story of Ghost, one of the supporting characters in the Modern Warfare universe.
Why it matters
Call of Duty has been the biggest franchise in video games land in both 2009 and 2010, managing to sell many millions of copies and deliver one of the biggest and most reliable revenue streams in the entertainment area, rivaling with huge movie franchises.
The next Call of Duty also matters because it's unlikely that it will maintain the same structure as those before it, with a rather short single player which is totally disjointed from the multiplayer element, which assures the long-term interest in the game.
Activision knows that it could monetize Call of Duty beyond the payment for the initial product and the map packs that arrive later so its very possible that we will see a version of the game delivered featuring only the multiplayer side, with a complex payment system and more emphasis on leveling.
And if Activision plays it classic with the next Call of Duty, it will be interesting to see whether the same level of sales can be maintained three years in a row.