The upcoming update for the Master Chief Collection will not only bring the collection to the PC, but also feature an “anniversary” edition of Halo 3 in order to appease fans and provide a draw for PC gamers to buy the game.
343 Industries, along with Microsoft Corporation, are planning on creating a single game called 'Halo' to be released as the next mainline Halo game, which will contain all future Halo first-person shooter releases, including all multiplayer updates and single-player campaigns.
The events of The Forerunner trilogy foreshadow the upcoming events of the Reclaimer Saga. The corruption of the most powerful AI (Mendicant Bias/Cortana) by the Flood, and the theft of a Halo by said AI, foreshadows dark times coming to the future of the Halo series.
The events of the Human-Forerunner War, the Human-Flood War, and the Forerunner-Flood War went EXACTLY how the Primordial/Flood wanted it, including the activation of the Halo Array and the annihilation of the Forerunners and the Flood.