Well this is a surprise. Microsoft has announced (via their PlayXBLA blog) that they’ve renewed the trademark to 90s fighting franchise Killer Instinct.
Killer Instinct was developed by Rare as an arcade showcase for the then-in-development Nintendo 64. A sequel followed in 1996, but the series has been rarely heard from since (Nintendo would release KI Gold in 1998). Microsoft purchased the rights to the franchise in 2002 along with their acquisition of the developer.
While PlayXBLA didn’t elaborate on what this trademark renewal means, the location of the announcement could possibly point to an Xbox Live Arcade re-release of the first two games in the series.