He will come in and whoop ass for like a month or two solid, position himself for a title match (I assume by then Apollo will have lost the US strap to Lashley) and either A: come out beltless due to fukkery or B: Win in convincing fashion.
Either way, following that he'll tread water or largely get the Bianca Belair treatment until Survivor Series rolls around and he and Roman (who will likely be champion around or not long after that time) have some sort of face-off during the invasion angle -- because the WWE is going to need shyt like that for their surely kick-ass video package surrounding the event -- where it's not that the brands on showing up on the other's turf, but rather the other's time. Best-case scenario from that, Roman will win the match for his team again, last eliminating Lee again, but Lee will challenge Reigns at Mania, ideally after winning the Rumble.
As Keith has said himself... he's a moment-maker. When it's time for a MOMENT? He'll get shine (see: him doubling up on titles at the Bash). Until then? Expect Belair treatment (spark when she started, fades to Main Event programming).