Assassin's Creed Shadows - first expansion name and details.
https://www.reddit.com/r/assassinscreed/s/J4aTXwpXjb
Not sure if the steam page was supposed to show this info yet as Ubisoft always does a "post launch content" video showcasing all future free and paid dlc.
Maybe it's intenional, maybe not. It's noteworthy that Ubisoft hasn't shared this ilnew info anywhere else.