#5 CM Punk

AEW's biggest signing would be that of former WWE Champion CM Punk, who walked away from pro wrestling after his departure from WWE in 2014.
Punk recently returned to the wrestling ring, albeit under a mask, for MKE Wrestling. Punk has time and again spoken about how he is no longer interested in returning to pro wrestling, but also revealed that if an offer was laid on his table, he may consider it.
Cody spoke about how Matt Jackson actually made an offer for Punk, in an interview last year: "Matt [Jackson] actually made a full offer or full pitch for his services and I think Punk is focused on the Mixed Martial Arts element of his career. One of the reasons we didn't first come out and say, 'Here's who we want you to wrestle,' because I think we just wanted him to be a part of the event for a lot of fans, he's captured their imagination even with the amount of time he's been gone," said Cody in an interview with WrestlingInc.
Punk's reply to Cody was an interesting one, as he said that an offer was not made, but also revealed that he was done with wrestling. His latest appearance at the indie show indicates that he may still love pro wrestling and a big offer could make him return!