PDCD1 and neoplasm: The programmed cell death 1 (PD‐1) receptor, a T‐cell checkpoint receptor protein, suppresses antitumor immunity in a number of malignancies, including NSCLC,5 and tumor expression of PD‐L1, an endogenous ligand of PD‐1, is associated with a poor prognosis.6 Nivolumab, a fully human PD‐1 immune checkpoint inhibitor antibody that disrupts PD‐1–mediated signaling and may restore antitumor immunity, is approved for the treatment of patients with metastatic NSCLC and disease progression on or after platinum‐based chemotherapy.