CM Punk is set to battle his bitter rival John Cena for the Undisputed WWE Title at Night of Champions. The Second City Saint has been on a stellar run in the Stamford-based promotion since returning at Survivor Series: WarGames 2023. However, his career may be in jeopardy come Night of Champions, thanks to a potential, massive twist.The rivalry between The Last Real Champion and The Best in The World has exceeded expectations. The two veterans have made their upcoming match a must-see in just a few weeks with their incredible promos and storytelling. While many fans expect John Cena to retain his title, WWE could introduce a shocking stipulation to add a layer of unpredictability to the bout.On last week's SmackDown, John Cena got the whole world talking with his version of the pipebomb promo, taking his ongoing feud with The Second City Saint to the next level. The Last Real Champion has been following a well-thought-out plan in his Retirement Tour. Cena's confidence could be on display on this week's SmackDown as well, as he could add a 'Loser Leaves WWE' stipulation to his match against CM Punk at Night of Champions.After the humiliation that Punk suffered at the hands of The Franchise Player last Friday, a chance to dethrone his arch-nemesis and end his Farewell Tour prematurely could lure the former AEW star into accepting the stipulation. This shocking twist would remove the predictability factor from the match and make it even more interesting.However, John Cena may again resort to underhanded tactics to beat CM Punk, forcing The Voice of The Voiceless to walk away from the Stamford-based promotion. Punk's controversial departure in 2014 sent shockwaves through the wrestling world, and it could happen again on June 28.That said, this angle is highly unlikely to play out, as Punk is seemingly enjoying his current stint with the global juggernaut and is an integral part of the main-event scene.Former WWE star believes John Cena's pipebomb was better than CM Punk'sWhile speaking on the REBOOKED podcast, former WWE star Matthew Rehwoldt (FKA Aiden English) compared John Cena's version of the pipebomb to the original. Rehwoldt credited CM Punk for ''laying out the carpet,'' but preferred The Franchise Player's version for its wordplay."I liked it better because of the way it riffed on it and the way he turned it on its head and made a hypocrite of Punk. All that wordplay was great, but you can't do that without an original to riff on. So, Punk gets credit for laying out the carpet, but Cena gets extra credit for doing it so well with flip-arounds and the way he kind of turned the mirror on Punk," Rehwoldt said.It will be interesting to see what creative direction the company opts for, as John Cena and CM Punk lock horns for possibly the last time at Night of Champions.