Undertaker and CM Punk wrestled each other couple of times in WWE, they both always made sure to entertain fans. Undertaker is one of the most respected wrestler in the whole of pro wrestling.
Undertaker recently gave an interview to Inside The Ropes where he talked about working with CM Punk in WWE
He was great to work with. I’m very proud of that match. We sat down and we thought about ideas and everything. It was great. I had no beef with Punk, he was always business with me. Hopefully, I was with him [too]. I’ve been told that I have some beef against him, social media… they tell me because I don’t read comments or follow it, but I have a lot of people that tell me. Supposedly I squashed his push and all of this but anybody who knows me – even if I didn’t like somebody, and I don’t dislike punk, that’s another rumour that I have disdain for him, I don’t, he was good with me and that’s all that matters – business is business, whatever’s best for business.”(H/T: WrestlingInc)