CD8A and neoplasm: In this study, we demonstrate that exosomes derived from PCa cells contribute to CD8+ T cell exhaustion via upregulating PD-1 and TIM-3 and perturbing the secretion of effector cytokines, such as IL-2, IFN-γ, TNF-α, and TGF-β, thereby reducing the tumor-killing ability of CD8+ T cells.