RecruitingPhase 3Drug trialA Study to Learn How PF-06821497 (Mevrometostat) Works in Men With Metastatic Castration-resistant Prostate Cancer.This study will explore whether a combination of the investigational drug PF-06821497 and enzalutamide will work better than taking enzalutamide alone in participants with mCRPC who are ARSi or abiraterone naïve.