Call of Duty: Modern Warfare 2 is a 2009 first-person shooter game developed by Infinity Ward and published by Activision. It is the sixth installment in the Call of Duty series and the direct sequel to Call of Duty 4: Modern Warfare. It was released worldwide on November 10, 2009, for Windows, PlayStation 3, and Xbox 360. A separate version for the Nintendo DS, titled Modern Warfare: Mobilized, was also released on the same day. A version for OS X was developed by Aspyr and released in May 2014, and the Xbox 360 version was made backward compatible for the Xbox One in 2018.

Call of Duty 4: Modern Warfare is a 2007 first-person shooter video game developed by Infinity Ward and published by Activision. It is the fourth main installment in the Call of Duty series. The game breaks away from the World War II setting of previous entries and is instead set in modern times. Developed over two years, Modern Warfare was released in November 2007 for the PlayStation 3, Xbox 360, and Microsoft Windows and was ported to the Wii as Call of Duty: Modern Warfare – Reflex Edition in 2009.