From PC Gamer:

"Brace yourself, it's announcement announcement time. The Call of Duty site has updated with a giant message declaring that a "Call of Duty world reveal" will arrive on May 1. Given mentions of the sequel in developer CVs and on Amazon, it seems likely that Treyarch will whip the sheets off a sequel to the stonkingly popular Call of Duty: Black Ops next Tuesday.

A marketing poster bearing the message "return for debriefing" with a familiar broody soldier silhouette appeared recently, evoking the angry debriefing sessions of the first game and adding more weight to the Black Ops 2 rumours that have been flying around recently.

Nothing has been confirmed by Activision yet. Perhaps they'll announce Call of Duty: Future Warfare and show an amazing roaming space shooter in a new engine. I'm not placing any bets on that, though. Love it or hate it, Call of Duty is one of the biggest shooters in the world. It's maintained its success whilst barely evolving at all for the last few years. Can that continue?"