It could be possible like halo 1 to 5. To be ported to steam. Though it could take a while. If so there should be a link your xbox live so you can choose to keep your stats. Like levels or Transfer to your steam account. Also theres a steam workshop so people could create custom Armour, skins and maybe even req weapons and vehicles. Which could be added to halo 5.
Could it be possible halo be ported to steam.