https://www.pcgamer.com/call-of-duty-black-ops-4-will-be-on-battlenet-not-steam/

Much of what we say in today's Call of Duty: Black Ops 4 reveal event, including Zombies, battle royale, and the absence of a single-player campaign, was expected. But Treyarch did drop one big surprise: The PC version of the game will be released exclusively on Battle.net.

"Those of us at Blizzard have been friends with Treyarch for many, many years. When it came to working on Overwatch, we consulted with Treyarch on a number of features," Blizzard's Jeff Kaplan said. "With all the features of Battle.net, I think it's going to be pretty amazing what Black Ops 4 is going to have to offer."