Rainbow Six Siege still has one more DLC pack left in it, and Ubisoft looks like it's almost ready to talk about it. The official Rainbow Six account tweeted the above image yesterday, accompanied by Japanese text which roughly translates to "time, come Tareri" (thanks, Google Translate!).
I'll be honest: I have no idea what "Tareri" could mean, but I think it's safe to say that a new map and operator pack is coming very soon, and that it will be set in Japan. I'm doubly sure of the latter, because a recent Twitter leak appears to confirm it.
Here it is, posted by user @JonKay20. The decor does look thematically linked to Japan, and in the closing moments the enclosed space is revealed to be part of a skyscraper. No doubt we'll be hearing more soon.
Season 4 Operator and Map pic.twitter.com/Y1nBfGIWamOctober 25, 2016
Although this appears to be the last promised DLC pack, there's the possibility that Ubisoft will continue to add to the game. A recent survey suggested that a whole new season pass – and thus, I guess, four new maps and operators – could be on the cards.