This could be a Xbox Cloud Gaming issue rather than a specific Halo one, but it’s important nonetheless.
A while ago, you could play Halo MCC PC via GeForce Now if you owned it on Steam (and/or maybe the Windows store), Halo was pulled out of GeForce Now (as well as other Windows games) to probably promote XCloud, which makes sense given that Windows wants to push that platform. The problem is now we can’t play Halo (or any other Windows published/owned game) using mouse and keyboard because the current iteration of XCloud only supports console only streaming (i.e. controller only).
Granted XCloud is in beta and the option to add M&K support was mentioned in a few places (or perhaps rumoured) but is there a timeline when XCloud could support the streaming of PC games through pass or when Halo could be added back to GeForce Now? Would be interesting to know what the development around this would be.