This year's Call of Duty game has surfaced on Battle.net as Call of Duty Slipstream. This is a dev build of the game which usually appears online before the official reveal.
Last year's Call of Duty was officially named Black Ops Cold War but before Activision actually announced the game and its title, a dev build named The Red Door surfaced on Battle.net. Of course, this was just a codename, which devs use to hide the real name of the game.
This year is no different. Once again, the Call of Duty game has appeared on Battle.net as a dev build but this time, with the name Slipstream. There's also a logo, just like last year with the Red Door. You can check out all the listed versions here.
Call of Duty games are usually announced during the summer but given that some rumours suggest this year's title is in a rough state and has development issues, it's possible that Activision decide to delay the announcement for later this summer.
Call of Duty 2021 is rumoured to be another WW2 game, helmed by Sledgehammer Games, the creator of the most recent WW2 title, which was not received very well.
It's expected that the new game merges with Call of Duty Warzone, offering a brand new setting and map for the free-to-play battle royale.
Keep in mind that these are just rumours at the moment, so it's possible that some of these are not 100 per cent accurate.