We're going to say this is a rumor for now, but reports are saying the latest issue of OXM UK is confirming Infinity Ward's next game will be a sci-fi shooter. Whether this is their next Call of Duty installment is yet to be determined. For all we know, this could be a whole new series since Infinity Ward has been saying for some time they want to do something different.
As popular as the Call of Duty name is and what it is known for, I can't really see them taking the series into the future yet. My guess is, it will be a new IP but then again, I'm just speculating.