Microsoft Game Studios recently posted a career opportunity ad that sheds some light on a  project that definitely sounds interesting. Below you can read an excerpt of the announcement with the relevant parts bolded.

Microsoft Studios is looking for an experienced Technical Producer to drive the future of gaming through a hybrid of AAA quality games and service-based experiences, technology, and business models. You will work with external game developers and an internal team of cross-discipline employees in Microsoft’s Xbox organization.

RESPONSIBILITIES:

- Lead the production, execution and integration of key technologies and features necessary to support the service components of a new game based on an existing, successful Microsoft Studios IP.

The first part of the description basically translates to "Free to play game of AAA quality with a business model based on microtransactions." We also learn that the game will be developed in collaboration between an external studio and internal developers.

Finally, the game will be based on an established and popular Microsoft IP.

Of course nothing official has been announced yet, and we have no idea on what IP will be involved in this project, but it's definitely interesting. It may very well be Microsoft's response to Capcom's PS4 exclusive Deep Down.