Updated 2: Rogue is already official:
Updated: Ubisoft has been busy deleting the leaked video from different streaming video services. I would try to compensate it with the following screenshot gallery extracted directly from the leaked video:
Ubisoft will commercialize two Assassin’s Creed games this year. Unity will be released only on PC, One and PS4. Owners of PS3 and Xbox 360 will delight Rogue on their systems.
Supposedly, Assassin’s Creed Rogue would be set between the events of Assassin’s Creed III and IV. Shay, a Templar sailor, could be the main character in Rogue. The year would be 1758 and the city, the always glinted New York in an era of sailors and pirates.
Check the first leaked video of Rogue for yourselves:
Apparently, Ubisoft would have recycled some assets and gameplay mechanics from Assassin’s Creed IV: Black Flag for Rogue.