His exit from the company was not unexpected because, as first reported last week by Raj Giri, Black requested his release but it was denied at the time. After his match at All Out where he was pinned, Black waved to the fans and bowed before hugging the other members of the House of Black. See below for the fan video of Black saying goodbye. It was believed after Sunday that he was done with the company.
Giri reported the following last week about the reason why Black wanted out of AEW: "I heard an AEW star requested their release, and follow up sources indicate it was Malakai Black. He reportedly has repeatedly shown concerns about his mental health due to personal life and demoralization due to the booking and handling of his character."
Black joined AEW a year ago after being released by WWE due to budget cuts. It's unknown what he plans on doing in the wrestling business but a "conditional release" would suggest that there might be a non-compete clause so a WWE return would not be happening anytime soon.