This will be (obviously) the sixth title in the series that began with Sid Meier's original, classic strategy game back in 1991. I must admit I thought this was a bit soon, but then I saw that Civilization IV (which I still think of as quite new) was released in 2005 and V (which I own but haven't played once yet) in 2010. I think I can safely say that it will be some considerable time before I get around to playing this.
Civilization VI will build on elements of V and will come with all of the features introduced in that game's DLC as standard. VI also promises to "unstack the cities" in the same way that V "unstacked the armies". VI will feature areas around each city where you can place additional buildings and facilities. The developers are also promising a stronger focus on AI and diplomacy than ever before.
If Sean Bean is a character in the game, I can confidently predicted he will be nuked to death by Gandhi before the endgame is reached.