Registered Insiders can participate in a beta for Age of Empires 3: Definitive Edition next month.
Player counts will be limited for the multiplayer beta, so if you want to a chance to be included, be sure to register for the Age of Empires 3: Definitive Edition test.
The initial test will have a small pool of players, but it will open up to more people in March (thanks, RPS).
Along with the small multiplayer test, the developer will also be seeking feedback on the game's campaign.
Age of Empires 4 is also in the works and is without a release date. If you want your fix in the meantime, Microsoft released Age of Empires 2: Definitive Edition back in November. It’s also available through Xbox Game Pass and Steam.