So far, very little is known about Call of Duty 2021 except that the game is in development. Activision has confirmed that a new Call of Duty game will be launching this year, but details beyond that are unavailable at this time. However, reputable leakers have started teasing the game's setting, though there seems to be a disagreement as to what the Call of Duty 2021 setting will ultimately be.
Leaker Okami has suggested that Call of Duty 2021's setting will be the Korean War, but leaker Victor Z on Twitter has said that the setting is actually World War 2. The Call of Duty franchise has long been tied to World War 2, with the first three games in the main series set during that time in addition to numerous spin-offs, World at War, and Call of Duty: WW2, so it's a pretty easy claim to believe.
Victor also suggests that Call of Duty 2021 is being developed by Sledgehammer Games, the same studio that developed Call of Duty: WW2. This makes the game's supposed World War 2 setting somewhat surprising, as one would think Sledgehammer would want to do something different for its next game in the long-running franchise. Of course, with conflicting information between leakers and no official details on Call of Duty 2021 to date, fans should take all of this information with a grain of salt anyway.
Leakers haven't just been talking about Call of Duty 2021's setting and the studio developing the game. Another well-known Call of Duty leaker, Tom Henderson, has suggested that Call of Duty 2021's subtitle is Guerrilla Warfare. Unfortunately, that leaked subtitle doesn't really help narrow down which leaked Call of Duty 2021 setting is accurate. Guerrilla warfare tactics were used in both the Korean War and World War 2 by and against various groups involved in both conflicts.
Unfortunately for those wanting concrete answers about Call of Duty 2021, they will likely have at least a few months to wait. Activision typically doesn't reveal new Call of Duty games until May or June of any given year, and in the case of Call of Duty: Black Ops Cold War, it waited until late in the summer to make the official announcement. With Call of Duty: Black Ops Cold War breaking from Activision's established pattern of Call of Duty game reveals, it's anyone's guess as to when Call of Duty 2021 will be shown to the public.
Whenever Call of Duty 2021 is revealed to the public, fans should find out definitively where the game is set, as well as which studio is helming the project and if it's really Sledgehammer Games as rumored. Until then, the rumors and speculation will continue.
Call of Duty 2021 is in development.