Shane McMahon vs. The Undertaker, while announced as a Hell in a Cell match for Wrestlemania 32, is not 100% set in stone. John Cena still wants to face Undertaker and we’re a week or two away from having a real idea of how realistic it would be for Cena to wrestle on the show. So the idea of shooting an angle to have someone “represent” Shane and wrestle The Undertaker has been discussed. The entire story is being booked “by the seat of their pants.”
Talks to bring back Shane McMahon began a few days after the Royal Rumble but the idea of him actually wrestling on the show is something that was really only brought up about a week before Raw. The company is obviously keeping everything very close to the vest, but we’re told Undertaker vs. Cena (or Sting in theory) is not out of the question. Although at this point, WWE prefers to pair off Sting (pending medical, something that's obviously an issue) with The Wyatts and go with Undertaker vs. Shane unless they feel very confident in the week or so that Cena can do the match.
Shane also ended up being way more over than anyone expected. Triple H ended up with egg on his face after trying to minimize how much people would even care about Shane coming back. Hunter was vocal that he did not view Shane as a legitimate opponent for Undertaker but after how Shane was received, Vince McMahon is confident in the match even if they don’t end up shooting an angle to slide someone into it as Shane’s representative.