#1 John Cena

Yes, John Cena did face The Undertaker at WrestleMania 34 and lost the match in under 3 minutes. This was a dream come true for many fans. But none of them thought that it would be a squash match.
No one was truly satisfied with the match they had. So it makes sense to have a rematch between them, and this time give the fans a competitive match that they wanted to see. There is no better time and place to do this other than SummerSlam 2018.
R-Truth wanted to 'kill' former WWE writer. More details HERE
Only 15 minutes on the whole show would give us the perfect match between John Cena & The Undertaker. It won't matter who picks up the victory but it would give us a memorable moment for the rest of our lives.
John Cena was the face of the WWE for almost a decade and The Undertaker is a living legend. This would be the biggest marquee match on the show and it can also be the last encounter they have with each other.
So these were the 3 wrestlers who could truly face The Phenom at SummerSlam 2018. Let me know in the comments about who do you think should face The Undertaker.