Implications of Programmed Cell Death 1 Ligand 1 Heterogeneity in the Selection of Patients With Non-Small Cell Lung Cancer to Receive Immunotherapy

The use of programmed cell death 1 ligand 1 (PD‐L1) as a predictive biomarker to select patients to receive programmed cell death 1 (PD‐1) or PD‐L1 inhibitors in non‐small cell lung cancer (NSCLC) is limited by the definitions of positivity, interassay agreement, and intra‐ and intertumoral heterogeneity of expression. Although PD‐L1 expression enriches for responses, the lack of expression does not exclude clinical benefit.