The tumor proportion score (TPS) is calculated as the percentage of cells staining positive for PD-L1 in immunohistochemistry among tumor cells, and the combined positive score (CPS) also considers immune cells (34); after KEYNOTE-048 (35), pembrolizumab is approved for R/M HNSCC with CPS ≥ 1 (which of course includes TPS ≥ 50%). The gene discussed is CD274; the disease is head and neck squamous cell carcinoma.