Not much is said on the matter, but PlayXBLA got the okay from the Microsoft legal team to announce the trademark renewal for the long-absent fighting game franchise, Killer Instinct. The morsel of information given lies within this single quote regarding KI: “We have either renewed or refiled a trademark application in various jurisdictions.”
Trademark renewals are not normally a subject to turn heads. Renewals are very common in either protecting past intellectual property from being used by another company, or to keep IP for future use. With recent stories claiming Microsoft canned an HD revival of Killer Instinct by Rare, the former purpose of the trademark renewal seems likely. With that said, it is quite rare (no pun intended) that a publisher would release this kind of information to a fan-facing outlet unless there are plans in place.
The last Killer Instinct release was the Killer Instinct 2 arcade cabinet in 1996 and its N64 port, KI Gold, later that year. No plans for any current ports or sequels have yet to be announced. Whether this is an unintentional troll or foreshadowing a revival, we are happy to once again see Killer Instinct has not been forgotten.