Programmed Death Ligand-1 (PD-L1) Expression in the Programmed Death Receptor-1 (PD-1)/PD-L1 Blockade: A Key Player Against Various Cancers

- Either PD-1/PD-L1-targeted therapy alone or in combination with other treatment modalities provides benefit for patients with advanced cancers. Because of the complexity of cancer immunity, we still do not have a reliable biomarker to predict the response of PD-1/PD-L1-targeted therapy. Future studies, including methods beyond immunohistochemical stains, are needed to develop reliable biomarker/biomarkers for pathology laboratories to aid in selecting patients who will benefit most from PD-1/PD-L1-targeted therapy.