Literally anything could happen. Neither has the chin to survive a war with the other. Might that make it boring, where they fight cautiously? Might that make it quick and brutal?
Wladimir would get KO'ed early, this fight would be before Wladimir joined Steward to learn him how to clinch, survive, and use his range. So my money would be on Lewis.
I don't think Wladimir would fight at the sort of range allowing lewis many chances to land uppercuts.
I think the fight might come down to whether it turns into a war or a technical fight. If its a war I favour Lewis. If it is technical then I think Wlad wins.