We already knew about Epic working on a cancelled game called Gears of War: Exile that was supposed to be played with Kinect. Now it turns out they were also planning a title called Gears of War Tactics. It was supposed to be played with both controller and Kinect and even reached the alpha phase of development.
VG247 reached out to Epic, who said they cannot comment on this anymore since Microsoft owns the IP. There we'll probably never get to know why it was cancelled, but here's som footage that was posted by VG Leaks. Honestly, it doesn't look that good which also might be why it never was finished.