#1. To potentially set up a feud against John Cena

John Cena made an incredible impact at WrestleMania 35 and set the wrestling world abuzz after he returned with his old "Doctor of Thuganomics" gimmick. It only made a brief return in 2012 during his feud against The Rock, but apart from that, it was a good 14 years before we had seen it in its full form.
Whether he will be returning with that gimmick or not, we don't know. But our best guess would be to say no. However, if his schedule is clear enough, we could see Cena return for a month or so for a one-off program against Lars Sullivan.
It wouldn't have to be an extensive feud by any means, but a rather quick 4-week build to a squash match. Squashing Cena would be the perfect way to get Sullivan over as an extreme threat.
Becky Lynch has been challenged HERE.