The less optimistic reading would be that Infinite's Campaign team has been gutted (it does look like most layoffs are on the Campaign team) but they didn't want to let go off Joe so they convinced him back to XGSP. In that scenario, it's likely that Infinite's Campaign expansion has been scrapped and they're instead doubling down on the Multiplayer, as a result Halo Campaign will be on ice for a while, likely no Campaign expansions for Infinite and no new Halo story until they release the next Halo title (10 year plan is likely scrapped at this point).