Subsequently, in 2017, the European Commission approved nivolumab for the treatment of the same patient population with HNSCC, followed shortly thereafter by pembrolizumab as monotherapy in recurrent or metastatic PD-L1-expressing HNSCCs with a tumour proportion score of ≥50% and in cases where progression occurred during or after platinum-containing chemotherapy [292,383,435]. Here, CD274 is linked to head and neck squamous cell carcinoma.