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.