[Update #2]: Ubisoft is also working on an Assassin's Creed game set in feudal Japan, and another with a much darker tone.
[Update]: Assassin's Creed Mirage has now been properly announced, and I'm happy to say that it's indeed going to be a homage to the original!
I hope you're in the mood for a bit of sneaking and stabbing as Ubisoft has just announced that they are working on a brand new Assassin's Creed game - Assassin's Creed Mirage. The exact details are currently still few and far between, though you won't have to wait too long to find out more as the full reveal will be going live on September 10th.
If you're willing to indulge some rumors, however, then you might be interested to hear that Assassin's Creed Mirage will be a spiritual successor to the original Assassin's Creed. In other words, the focus is going to be firmly placed on stealth, while the more recent RPG mechanics will be taking a back seat.
Additionally, the story will be entirely set in the past and will have an extremely limited modern day presence. Personally, that's the rumor I really hope ends up being true because the modern day parts in recent Assassin's Creed games have felt more like needless filler than actually exciting bits of narrative.
Whatever the case may be, I'll make sure to let you know once Ubisoft properly announced Assassin's Creed Mirage. Until then, I'm afraid all we can do is sit and wait.