Phil Brooks, better known as CM Punk, left WWE after the Royal Rumble PPV in 2014 and decided to sign with UFC to pursue a career in MMA. Many, including myself, wished him the best in this endeavor and waited in anticipation for his debut. It was eventually announced that Punk would face Mickey Gall.
His UFC debut left much to be desired though, as Punk tapped out 2:14 into the first round at UFC 203. This has led many to speculate as to just how much longer Punk would be in UFC. Since then, many WWE events have hijacked by "CM Punk" chants; however, Punk has stated on multiple occasions that he is fully committed to UFC.
Recently though, WWE officials, including RAW GM Kurt Angle have stated desire for CM Punk to return. I have no doubt that Punk would be welcomed with open arms, by officials as well as the fans. This being said though: If CM Punk does return to wrestling, I don't believe WWE would be his first choice (I would honestly believe Punk would go to GFW before WWE). Most likely I would say he would either go to Ring of Honor or New Japan. One thing that has been made clear by wrestlers as of late: WWE isn't necessarily needed to make a name for themselves anymore. And Punk has his reputation already made.
But let's say Punk does come back: what would be next for him?
Direction(s)/Opponents for CM Punk?
Brock Lesnar
As part of Punk's feud with Paul Heyman in 2013, Punk faced Brock Lesnar at SummerSlam. The only drawback is that now, Lesnar has pretty much gone straight to a 10+ German suplex, F5, pin and win formula that is virtually never deviated from. I doubt Punk and Lesnar would have a match reminiscent of what they did four years ago.
John Cena
An oldie, but it never hurts to go back to classical material (provided it isn't overdone). The Summer of Punk was one of the best angles ever done. What would be even better is Punk and Cena both blurring the face/heel dichotomy, with fans feeling conflicted as to who to put their support behind.
A.J. Styles
I know this would be labeled as a feud of "indie darlings", but the matches they would have would be phenomenal, pun intended. Given the right time and place, there would not be a person sitting down if these two clashed in WWE.
Kurt Angle
This one would be a stretch, but it would still be interesting to see. This is especially true if they kept CM Punk true to his anti-authority mantra.