If you've been eagerly awaiting the arrival of Halo: The Master Chief Collection on PC, but still want the option to easily jump over to your console and continue playing the game over there, it looks like your fairly specific needs are going to be met.
According to a tweet from 343 Community Director Brian Jarrard, cross platform progression should be available in The Master Chief Collection from launch.
Progression, unlocks, stats, etc.. will carry over between PC/console. In terms of playing together crossplatform, currently not planned for launch but it's something the team is accounting for and will evaluate over time.
— Brian Jarrard (@ske7ch) May 2, 2019
Jarrard does make it clear that while cross platform progress is planned for launch, playing multiplayer or co-op with your friends on other platforms probably isn't going to be a day one feature, if it ever happens. It's something they're aware of desire for, but it seems like a "maybe one day" kind of feature rather than a core aim of the port's design.
While The Master Chief Collection is due to release on PC some time this year, the first tests for Halo: Reach were recently delayed, with no word when they will happen, so we might see that full release window slip a little too.