Beginning with Modern Warfare, which is set in modern times, the series has shifted focus away from World War II.
The earlier games in the series are set primarily in World War II, including Call of Duty, Call of Duty 2, and Call of Duty 3. Several spin-off games have also been released. The series began on the PC, and later expanded to consoles and handhelds.
Call of Duty is a first-person and third-person shooter computer/ video game franchise.