As part of a statement from 343 Industries via Halo Waypoint, it was stated by Spencer that they are "excited about the prospects of an official classic Halo experience making its way to PC."

This all came about because 343 Industries and Microsoft had to take action against a recent "ElDewrito" PC release. This was a community created project that tried to revive the long dead Halo Online that was exclusively released for the Russian market back in 2014. ElDewrito took all of those assets and released what was essentially a hacked together Halo Online. The problem is, the team never obtained permission to do any of this and was thus infringe on the Halo IP. Whoops.

The important part about all of this is how the team would like to see Halo make its way to the PC but in an official capacity.

This sentiment was then echoed by Phil Spencer via Twitter shortly afterwards.

This could indicate that there are, at the very least, some plans to see Halo: The Master Chief Collection actually make its way to the PC some day. This would presumably only come after they fix some of the outstanding issues still present on the Xbox One version. Of course, with Microsoft's push to have release parity between the Xbox One and PC on their first-party titles, this could mean we will also see Halo 6 release on the PC day and date with the Xbox One release.