TLDR: DMZ is part of Warzone not MW2. With MW3 we're not getting a new Warzone, but because MW3 we're getting an updated Warzone, and that means DMZ too. FOR FREE!
Warzone's free-to-play DMZ extraction mode will remain available to access through the Warzone section of CoD HQ app. DMZ will continue to be fully playable across all existing maps, including Al Mazrah, Ashika Island, the Koschei Complex, Building 21, and Vondel.
Powered by a new version of the IW engine, Modern Warfare II continues to support cross-platform multiplayer and also features a free-to-play battle royale mode, Warzone 2.0, a follow-up to the original Warzone, all within a single cross-game launcher, known as Call of Duty HQ.
As of September 21, 2024, Call of Duty: Warzone!" Caldera will shut down, as our teams focus on future Call of Duty content including the current Warzone free-to-play experience. We all have had incredible Warzone experiences across the Call of Duty franchise since its first launch, including those in Warzone Caldera.