There's plenty we don't yet know about the story of Halo Infinite. One teaser might have just cleared things up a little, in regards to when the story of the upcoming sequel takes place in the overall Halo universe.
Yesterday on July 20, the Halo Instagram account posted a brief teaser of the initialization sequence for the Master Chief's suit. One user on the Halo subreddit found that if you slow down the rapid text flashing by on the screen, you can just make out: "Modified, Halsey, 09/9/2561."
Dr. Catherine Halsey was the architect of both the AI Cortana and the Master Chief, and this clip denotes that the doctor last updated the Master Chief's suit in the year 2561. This is three years after 2558, the year in which Halo 5: Guardians takes place.
Like we said, we barely know anything about the overarching story of Halo Infinite. All we know for now is what was revealed in last year's 'Discover Hope' trailer: the Master Chief is stranded in space, and an unseen enemy is seemingly pursuing him and the unknown human that he's rescued by.
Halo Infinite's story should become a lot clearer later this week. Microsoft's first-party Xbox Series X games showcase is set to take place on Thursday, July 23, and 343's Halo Infinite is the only confirmed game for the showcase so far. Microsoft already confirmed that we'll be seeing campaign footage of Halo Infinite, so the event should help establish the story of the next game in the Master Chief's saga.
Previously, we've been left to put the pieces together with past Halo Infinite teasers, when a previous teaser for the game indicated that the main antagonists from Halo War 2 could be returning. Elsewhere, a leaked toy set for the upcoming game might have revealed the fate of a particular character from Halo 5: Guardians.