Microsoft just announced that Age of Empires IV is in development by Relic Entertainment, creators of the Company of Heroes series and other beloved strategy games.
Other than its existence, and the intention to publish the game on Windows 10, Microsoft revealed almost nothing about the project. Judging by the animated concept art in the trailer, Age IV won't take the series to a significant new era. However there are armies from a variety of periods featured in the footage: Native Americans (Comanche, if I had to guess), British Redcoats, Roman legionnaires, and Japanese samurai. It's unclear how these different factions will fit together. Will these armies be individually purchasable, as in Company of Heroes 2? Hope not.
Relic has added a few words on its own website about the announcement.
Age of Empires IV will be Relic's first game produced for a publisher other than Sega, it's owner, since it was purchased by auction in the selling off of THQ's assets in 2013. It's unclear how this relationship between Relic, Microsoft, and Sega is functioning, but it's great that Microsoft was able to secure them for this.
Age IV is a separate project to Age of Empires: Definitive Edition, the remaster of the original game that was announced at the PC Gaming Show at E3. As part of the announcement, we also learned that remastered versions of Age of Empires 2 and 3 are in the works.
In 2009 Microsoft disbanded Ensemble Studios, the original creators of Age of Empires, eight years after acquiring it in 2001.