The expression of PD1 on expanding or infiltrating TILs on ICB is a matter of debate since both PD1− and PD1+ CD8+ TILs have been shown to mediate the anti-tumor effect of PD1 ICB.36 40 It is possible that this discrepancy may be due to differences in expansion of peripherally recruited PD1− CD8+ T cells and pre-existing PD1+ CD8+ TILs. The gene discussed is PDCD1; the disease is neoplasm.