Although Sipuleucel-T vaccine, an active cellular immunotherapy, improved overall survival among men with metastatic castration-resistant PC (CRPC), therapeutic effects of ICIs are limited for various reasons: low tumor mutation burden with less number of neoantigens, insufficient tumor microenvironment accompanying fewer CD8+ T cells and increased number of regulatory T cells and less PD-L1 expression in advanced PC14,15. The gene discussed is CD8A; the disease is neoplasm.