The listing notes Microsoft is looking for a highly experienced senior game developer to help build and lead the team for a new AAA title within an established and well-loved strategy game franchise. The actual name of the game series isn't mentioned but the most likely candidate is Age of Empires because this is most successful strategy series that was published by Microsoft.
The listing gives no further indication of what the game is or for which systems it is intended to release on. Microsoft Studios' best-known strategy series is likely Age of Empires, which has not seen a new entry since the free-to-play Age of Empires Online debuted in 2011.Source: CVG
Microsoft announced in September that Age of Empires will be pulled offline on July 1, 2014, though new players have been unable to join the game since then.