The game is a part of 2024's Call of Duty: Modern Warfare II and 2024's Call of Duty: Modern Warfare III, but does not require purchase of any of the parent titles. It was introduced during Season 1 of Modern Warfare II content. The game features cross-platform play and a new extraction mode titled DMZ.
However, if you do own Modern Warfare 2, then Warzone 2 has appeared within the main menu as an option, so you don't need to install it separately.