VSIR and posterior cortical atrophy: PD-1 has been identified on the surface of PCa-infiltrating CD8+ T cells 113, its ligands PD-L1 and PD-L2 are frequently overexpressed in the prostate TME 114, 115; in addition, the compensatory upregulation of VISTA in PCa that is treated with ipilimumab suggests an emergent role of this checkpoint that warrants further investigation 116.