II) Roman Reigns
Sooner or later, The Tribal Chief is coming to seek his Championship from Cody Rhodes. SummerSlam can be a huge stage who makes this dream rematch happen. But possibilities for this match at the mentioned stage are very low since WWE is focusing more on building The Rock vs Roman Reigns for WrestleMania 41. We might not get to see Roman Reigns challenging for the title before that. But there is definitely a thin possibility.