Infinity Ward, the studio that originally conceived the Call of Duty series of first-person shooters is no longer the same company it once was. Over the years, the studio saw the departures of its founders and many key developers. The studio's most recent shooter, Call of Duty: Ghosts, is widely regarded as the worst entry in the series.
The studio has not confirmed whether they will be helming this year's entry, but there's a good chance they will be, as Treyarch only just released Black Ops 3, and Sledgehammer Games is still working on their own entry after Advanced Warfare. The studio has not announced where it plans to take the series, so we can only imagine what they'll do. Could we see a Call of Duty set in the Vietnam War, or perhaps in the far reaches of space? Only time will tell.
The studio took to wishing gamers a happy new year a couple days ago. With any luck, they'll make a proper announcement soon.