ICIs are able to unleash anti-tumor immunity and mediate durable cancer regressions (13) via inhibition of pathways like the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death-1 (PD-1), and programmed cell death ligand-1 (PD-L1). The gene discussed is PDCD1; the disease is neoplasm.