Good news, a recent leak about the script of the game hints that it will likely be another installment in the Modern Warfare story arc. Here's some of the lines from the script:
"Reminds you of Phuket, doesn’t it? Only this time the dust gives you cancer… OK, park yourself and get ready. When this thing kicks off, put a hole in anything that moves."
"This is Sentinel Zero One, successful crypto change on C2 net break, requesting immediate update of blue force picture and status of artillery, over. I have you broken and unreadable, I say again, requesting updates to friendly positions and status of arty support. Do you read, over?"
"We’ve got KVA on the move! They’re going to strongpoint the main gate, ETA two mikes! We’re providing support for our heavy rollers! Ready up and let’s move!"
"Goliath, this is Sentinel Zero One! We have enemy armor at the gate, hundred meters north of our position! Requesting close-air grid mark three-one-six!"
It's worth nothing that, this is the same inside source that had information about Sleeping Dogs well over a year before the launch date that ended up being 100% correct.
All in all, it was a certainty that a new Call of Duty would launch next fall however, it looks like any rumors of a reboot or new time period just got a lot more far-fetched.