Rey Mysterio’s WWE contract that was signed in September 2018 has an opt-out clause after 18 months. This means Mysterio could opt-out and leave the company around WrestleMania next year. However, it’s important to consider that WWE often adds times to contracts when talent miss time due to injury and Mysterio missed time due to a shoulder injury.
Given the fact WWE has plans for Mysterio’s son Dominik to wrestle in 2020, it’s unlikely he opts-out.
WWE currently has plans for Mysterio to face “The Fiend” Bray Wyatt for the WWE Universal Championship in Mexico on 11/30. It was originally planned for Cain Velasquez to team with Mysterio at the show but instead, he’ll team with Humberto Carrillo.