Just because there was no sign of Halo at E3 2017 doesn't mean Microsoft has forgotten its flagship series. In fact, the company has made several announcements as part of its "Halo Summer Celebration" that fans should appreciate.
2017 marks the 10-year anniversary of Halo 3 - the original conclusion to Bungie's sci-fi epic. And while a remastered / remade "Halo 3 Anniversary" is not a thing, there's still some Halo 3-themed goodies coming. For one, you'll soon be able to play the game (along with Halo 3: ODST, Halo 4, and Halo CE: Anniversary) on your Xbox One via backwards compatibility. Every Halo map pack from the Xbox 360 era will also be made free so you don't have to worry about your experience being incomplete.
If you prefer your Master Chief a bit more modern but still want to celebrate Halo's legacy, a Halo 3 Anniversary Throwback playlist in Halo 5 will include fan-built Halo 3 maps and utilize "classic" gameplay settings. Developer 343 Industries hasn't revealed which maps these will be or what it means by "classic gameplay settings," but I imagine we'll know more as the playlist gets closer to going live.
Further down the line, Halo 5 will be getting a 4K upgrade for Xbox One X owners. Microsoft and 343 say more info on that is coming, but for now it's described as a "true 4K" upgrade.
Outside the realm of games, there are new toys, collectibles, merch, comic books, and novels slated to release over the next few months. Hopefully all of the above can keep us busy until official word of Halo 6.
Have you taken a tour of the Halo museum at 343's offices? Take your time looking through the photos - it's gonna be awhile before we see the next Halo game.