ICIs targeting the programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) pathway show significant efficacy in HL, but limited benefit in NHL subtypes including diffuse large B-cell lymphoma; in T-cell lymphomas and natural killer (NK) cell lymphomas, PD-1 inhibitors demonstrate significant efficacy in extranodal NK/T-cell lymphoma, but response rates remain limited for most peripheral T-cell lymphoma subtypes. The gene discussed is PDCD1; the disease is T-cell non-Hodgkin lymphoma.