CD274 and head and neck squamous cell carcinoma: Indeed, the PD-1/PD-L1 mAbs pembrolizumab, nivolumab, and atezolizumab have been approved by the United States Food and Drug Administration (FDA) to treat patients with advanced non-small-cell lung carcinoma (NSCLC), head and neck squamous cell carcinoma (HNSCC), and melanoma 6-8.