Although, research has mainly concentrated on the effect of PD-1 blockade on T cells, the recurrent deficits in major histocompatibility complex class I/II-associated antigen presentation in DLBCL cells suggested that the inhibition of PD-1 also involve additional mechanisms of action to that of cytotoxic T-cell-mediated killing in these lymphomas [112,113]. The gene discussed is PDCD1; the disease is lymphoma.