I'm not sure if he's going to run again or hang it up, but I'd be pretty surprised if an out-of-touch nutjob like himself would voluntarily retire. Unless the writing on the wall was size 600 Comic Sans, I doubt that dipshit could read it.
The other thing is that people in Wisconsin barely even recognize his name, even though he's the senior senator here. Last poll I saw said something like 35+% of WI residents "have no opinion" on the guy, which is absolutely wild considering he's been in office for 10 years. He may have hurt his chances by trying to steal the election for Trump but other morons like Hawley and Cruz have provided him cover. As much as Johnson should be forced to resign, the only public calls seem to be for the former two pieces of shit.
The guy to keep an eye on is Mandela Barnes, our young, Black Lt. Governor who you may recognize from the DNC. He hasn't announced yet but I would imagine he'll run and if he does, he should sew up the nomination pretty easily. He was great on the campaign trail, even in rural areas, and he'll drive massive turnout in Milwaukee and Dane Counties which is our best road to winning.