Treyarch has worked on every Call of Duty game in some capacity since Black Ops 4. The fact that they still make the best content out of the three main studios(in my opinion) is a miracle in of itself. They are easily the most overworked studio of Call of Duty right now.

@blurthurusion @imac234_ treyarch had been using the IW engine from 08 and just modifying it over time, Cold war used a heavily modified version of BO3s engine. Only reason they use IW current engine was because they were forced too, that’s why it took 2 years for bo6 cus they had to learn a new engine.