I found this 2 seconds ago, literally. After Black Ops Mw3 is the next game, though not confirmed it's looking that way! One thing we know is there is another Call Of Duty in development.
Quote from Activision CFO Thomas Tippl:
Originally posted by another user
“What we have said is that Infinity Ward is working on a Call of Duty title and you’ll hear more details as we advance through the year.”
Although Activision did not confirm this fully, it is likely to be Modern Warfare 3 – as Infinity Ward look to continue onwards with the next entry in the series, despite having most of their developer team whiped out.