As tweeted by Ubisoft:

This is the next big AC game which has been in development under the title Codename Red. Ubisoft has confirmed it'll (finally!) be set in Feudal Japan, hence the setting for the above teaser, and allow a "very powerful shinobi fantasy". It'll also be part of the Assassin's Creed Infinity platform - some kind of hub for all future games in the series that'll also facilitate multiplayer.

I'm excited to learn more about all of this. I've had a lot of fun with AC games over the years but am often left with the frustrating feeling that they fall just short of fully satisfying their potential. Here's hoping the next generation of games is the one to really stick the landing.