The next Assassin's Creed game is probably called Origins and it's probably set in Egypt. We don't know for sure, but a screenshot has leaked which purportedly comes from the game and not only shows the player very much in Egypt, but also captaining a boat, suggesting that the rumor that ship to ship combat and exploration were making a comeback for the game are accurate.
The screenshot seems to show the same male protagonist spotted in previously leaked screenshots of the game, and the fact that the player is being told to "follow Shadya to Khenut," suggests that Egypt is the location of the game, because Khenut was one of the wives of Egyptian king Unas, who ruled during the mid 2300s BC.
The protagonist is also being sent on a mission to "Assassinate the Crocodile," which has led to many a joke about captain hook, but is likely to be a title, rather than an actual crocodile, due to the way it's capitalized.
The Redditor who leaked the screengrab, shoutouttoashraf (account since deleted) also revealed information about the game. They claimed that Origins would have shorter segments that jumped around to different time periods and that many of the developers from Assassin's Creed IV: Black Flag, were working on this one.
They also said that we would first hear about the game officially from Ubisoft by the end of the month, with the big reveal happening at an E3 press conference.