KN1GHTMARE
Former Moderator
Rock Band and Dance Central studio Harmonix cancelled an "unannounced Xbox One Kinect title", according to the CV of a senior level designer at the studio. Uncovered by internet sleuth Superannuation (writing for Kotaku) the CV doesn't offer any details on the title other than it "was eventually cancelled".
In June 2012, Harmonix confirmed that it was working on "three and/or more" original IPs. John Drake, director of communications and brand management at Harmonix, said at the time: "Some of them are music games. Some of them are not full-on rhythm action games."
Source: CVG
While I personally am not big on rhythm games, it is still disappointing to see Xbox One games cancelled during a time when the game library is still very limited. I'm sure Harmonix will have plenty of releases on all consoles, but sadly we may never know what game was cancelled.