He said on Twitter that he tested positive.
Thankfully, I don't want to speculate, but he is vaccinated, and Omicron is relatively mild for vaccinated people, and some experts in the field are even hypothesizing that vaccination+a mild variant like omicron will build super-immunity for future variants. I really hope that is true, and I really hope he is feeling fine.
That said, let's not beat around the bush: having him do regular TV tapings (and house shows?) when cases were surging like crazy, knowing he is immuno-compromised, was wildly irresponsible. I mean, people were afraid this would happen for weeks now, including Vince and WWE management. This didn't come out of nowhere.