There were already some talks about the game going back to Black Ops and that this time it might focus on the Cold War and now Activision confirms that but announcing that the new game will be called Call of Duty: Black Ops Cold War.
It was added that the game might bring us back to where the game started but we do not know how much of the original game will be carried over or if the developer plans to offer something completely new.
The original Black Ops game was set back in 1960 and was set during the Vietnam War. More details about the new game should be arriving soon.
As for the current Call of Duty games. Modern Warfare which was released last year was a huge success and that was followed by another Modern Warfare 2 released this year which was pretty well received as well.