Yes, annoyingly if you just want to play Modern Warfare you still have to have Warzone installed.
This update includes these optimisations and is necessary to reduce the overall footprint, the company insisted. This reduced file size will come after "a larger than usual, one-time update" for Season Two Reloaded, Activision warned. "Enhancements to the overall content management system have been made possible through data optimisation and streamlining content packs needed for individual game modes," Activision said.
It got so bad that in February, Activision warned a standard 500GB PlayStation 4 may no longer fit Call of Duty: Warzone, Black Ops Cold War and Modern Warfare.
Call of Duty: Modern Warfare and Warzone have a reputation for enormous update downloads and massive install footprints, which we've reported on in the past. This is particularly welcome given how much space the recent Call of Duty games take up.