Update: A Halo: The Master Chief Collection announcement for PC seems all but certain at this stage, following an exchange on reddit between a fan and a 343 Industries employee.
In a thread entitled "I will buy the first 343 employee that comments on this pizza if MCC for PC gets announced during the special announcement this month", a verified 343 Employee account operated by Community Director Brian Jarrard responded: "What kind of pizza are we talking about?"
Original story:
During a week rife with rumors of an imminent PC port, Microsoft has promised "exciting news" related to Halo: The Master Chief Collection for its Inside Xbox show next week. The show, which Microsoft hosts every month, will air on Tuesday.
There's no guarantee that the PC port will be announced then, but recent reports have made it seem likely that the game is on its way. In a recent YouTube vid, Xbox expert Brad Sams claimed the game is definitely in development, that its release is fairly imminent, and that it's possible an unveiling will occur at E3 2019.
Still, history shows that Inside Xbox isn't an outlet for major announcements: it's more of a community update presented as a talk show. Meanwhile, changes and fixes continue to be applied to the Xbox One version of The Master Chief Collection, though it seems unlikely that a whole episode would be reserved for the announcement of patch notes (but maybe?).
But it does seem certain that the game will come to PC, just as the eventual arrival of the Xbox Game Pass seems to be a dead certainty. If Phil Spencer is to be believed, it'll be a year of big announcements for Microsoft's PC interests.