CD274 and head and neck squamous cell carcinoma: A pooled analysis from six prospective clinical trials of 589 patients with recurrent or metastatic HNSCC receiving ICIs also revealed a higher ORR in HPV-positive HNSCC irrespective of PD-L1 expression [21.9% vs. 14.1%, odds ratio (OR) = 1.79; p = 0.01] [22].