Halo Infinite has long been expected to have a multi-year plan behind its growth and development, and this recent trademark filing may offer a hint as to where the story is going.
Without spoiling, Halo Infinite takes place on Zeta Halo, which is one of the more ancient and mysterious of the numerous Halo rings of the franchise. Early on, elements of the story refer to a mysterious new faction, dubbed The Endless, and you'll find out more as you play through the campaign.
The trademark covers all the usual services and goods you might expect from a DLC: game software, online entertainment services, merchandise, and so on. Beyond that, it offers no concrete description as to what this could be specifically.
I don't want to give away too much about Halo Infinite's story, but it's plain from the game's open world and massive unexplored Zeta Halo ring that there's a mountain of content that 343i and Microsoft could explore, using the base Halo Infinite as its canvas. The engine is in place, and the structure of the game world lends itself well to potential add-ons — it's easy to imagine additional parts of the Halo ring becoming accessible, either above or below ground, or both. The Halo universal lore is also so expansive, there are all sorts of factions and history Microsoft could potentially add to the game to keep its story ongoing.
I expect The Endless will tie into the next Halo Infinite multiplayer season update, which is due some time next year before or around the summer, giving players ample time with the season 1 battle pass. Halo Infinite will also pick up co-operative play and Forge mode next year too, and it's always possible The Endless could launch to coincide with one of those updates as well.
Halo Infinite has recaptured much of the greatness the franchise lost since Halo 5, and combined with the highly-polished and free-to-play multiplayer, should serve as a potent springboard to propel Halo back to the top of the relevancy pile. Questions remain, though. Will any future DLC be included for free with Xbox Game Pass, much like Gears 5: Hivebusters was? Or will they be separate add-ons more akin to Destiny 2? Only time will tell.