Halo: Reach for PC: Launch Time, Pre-Loading, Crossplay, and More - IGN
Halo: MCC update brings Xbox Series X/S enhancements, Halo 4 on PC, & crossplay | Shacknews
Halo: The Master Chief Collection Will Have Cross-Progression between PC/console. Cross-Play is Being Evaluated, but currently not planned for launch. : r/xboxone
Halo: Reach - Official minimum 1080p & 4K PC requirements revealed, cross-play support detailed
Will 'Halo Infinite' Multiplayer Be Cross-platform?