For all of last generation, and the first two years of this one, Activision and Call of Duty buddied up with Xbox, with the games being co-marketed solely for the Xbox version, and all DLC coming to the Xbox version of the game first, with other consoles getting it later. However, that changed with 2015’s Call of Duty: Black Ops 3– and it may continue this year, too.
The official Twitter account for the game recently posted about the livestream this week that finally takes the wraps off the game, and that tease ends with a PS4 Pro ad- which seems to indicate the co-marketing deal with PlayStation for Call of Duty continues this year. Given that, it is also reasonable to assume that DLC for the game will hit PS4 first, and other platforms 30 days later.
Call of Duty: Black Ops 4 is due out on PS4, Xbox One, and PC this October. The game allegedly has no single player campaign, but does have a battle royale mode; the latter, standalone, may also be coming to the Switch.