Yup, CM Punk, Phil Brooks, whatever his name is right now. I'll just assume since you don't watch WWE you'll need the long route again. :P
CM Punk walked out (said to Vince McMahon go fuck yourself and went home basically) on the WWE over a year ago in January 2014. Nobody was really sure why and stuff and it was the topic since Punk was one of the top guys. I'd say it's like Chris Weidman quitting UFC and not appearing in public, it raises some questions.
He then appeared on a few things like the Talking Dead or some red carpet appearance but never talked much about why he quit WWE and what the fuck happened. Until November when he was on Colt Cabana's podcast (Colt is one of Punk's best friends) and talked about it. Basically his main issues were never getting to be in the WrestleMania main event even though he felt he deserved it year after year but more importantly, his health was shit and pro wrestling has a huge mentality of "Suck it up, you want to become something you'll have to prove you can become something so go out there and work, DAMMIT!"
And one factor of his health was that he apparently had MRSA for months without the WWE doctor doing something about it even though Punk was like "Doc, what's the lump in my back?" - "Uh, nothing, fatty deposit, have antibiotics, go out there and work!" And he says he was on antibiotics for months (and shit his trunks on TV one night because that's what antibiotics do to you) so apparently he had MRSA for months, which the Doc either didn't recognise, was too lazy or some shit. Also some other stuff like Punk was coming back from injury, didn't have a check-up with the operating doctor to be cleared to wrestle yet and the Doc just called the guy who did the surgery, was like "Punk's doing better, can we clear him to wrestle...great, awesome!" even though Punk himself said he wasn't clear to wrestle yet.
So, heavy allegations against the doctor, alright. But more importantly: When Punk went home WWE argued he was in breach of contract (even though he wasn't, don't ask me how their contracts work) and they didn't owe him royalties, Punk lawyered up, sued them, they settled by paying him a million, or two, or so. And WWE is like a jealous ex-girlfriend. If they can do something to ruin your life, they ruin your life.
So Punk is now training to prepare for his UFC debut and what do they do? "Hey Doc, sue Punk for slander about that podcast, you didn't do that, right? Here, we give you "evidence" you didn't do that. We also have lawyers already. Come on, sue him!" So yeah, officially the doctor sued CM Punk but realistically he's just a figurehead for WWE to get revenge for having to settle last year. And oh yeah, they also sue Colt Cobana for giving Punk that platform to slander. And Cabana is working indies so his finances are much more limited than Punk's, so that's also great, not just fucking with Punk before his UFC debut but possibly ruining Cabana's life as well, given that they want a million fucking dollar from him.
Sorry if that was too long. And full disclosure: I'm a CM Punk guy and hate a lot of that crap that is going on in the WWE so this is somewhat biased.