Microsoft Game Studios are developing the 'next instalment in a beloved strategy game franchise', according to a number of job listings on its career site.
The company's Decisive Games team, which 'is focused on world class strategy game development', is hiring three senior software engineers to work on its latest project. The job listings also asks for 'familiarity of Direct X11 or Xbox 360/Xbox One rendering APIs.'
Given that Microsoft will announce Windows 10 soon and that the job listing mentions both “Windows and Xbox,” we are guessing that this means the game will arrive on both formats.
It's unknown what this franchise could be, but speculation points to Age of Empires or potentially, Halo Wars.