Not that it would surprise anyone, but an ex-Bungie employee recently posted in their online resume (not saying who or linking, sorry) that they worked on Bungie's as-yet unnanounced Next Project, and that it used a "modified version" of the Halo engine.

Given that even Halo itself could be said, broadly, to have been prototyped in a "modified Myth engine" and that every Halo game used a modified version of the engine of the game before it, there's nothing Earth-shattering about this, but... for what it's worth, it would appear that Bungie's next game at least has some connection to the work the company has done on Halo in the past decade, and isn't a complete technological departure.