2020's Call of Duty: Black Ops Cold War cost over $700 million to make. 

The news comes via a court filing in the case against Activision by the parents of victims of the Uvalde school shooting back in 2022, as spotted by Game File.

Specifically, they come from the publisher's head of creative for the Call of Duty franchise, Patrick Kelly, who said that  Black Ops Cold War racked up $700 million in development costs and that the shooter had shifted 30 million copies.

Meanwhile, 2015's Black Ops 3 shifted 43 million units and cost $450 million. 2019's Call of Duty: Modern Warfare reboot cost $640 million to make, selling 41 million copies. 

It's worth noting that these development costs are over the game's lifecycle, meaning they will represent several years of work on each release, plus the creation of live-service content. Call of Duty games don't tend to have super long post-launch plans so the bulk of the cost will be pre-release.