Cheats can be unlocked by collecting intel (Call of Duty 4: Modern Warfare) or Death Cards in Call of Duty: World at War to unlock something special like unlimited ammo.Call of Duty is a first-person and third-person shooter video game series franchise. The series began on the PC, and later expanded to consoles and handhelds. Several spin-off games have also been released. The earlier games in the series are set primarily in World War II; starting with Modern Warfare, set in modern times, the series has shifted focus away from World War II. Modern Warfare was followed by Modern Warfare 2, set in modern times, and Black Ops, set during the Cold War. Modern Warfare 3, also set in modern times (as the name suggests), was released on 8 November 2011, and "Black Ops 2" being set in both the Cold War, and in a near-future setting.Cheats are unlockable options available that will either make a game easier, harder, or add a humorous aspect to it. Cheats are available in Call of Duty: Finest Hour, Call of Duty 4: Modern Warfare, and Call of Duty: World at War.