PDCD1 and head and neck squamous cell carcinoma: Promising efficacy with anti-B7H3 mAb Enoblituzumab plus pembrolizumab with a response rate of 33% in platinum failure anti-PD-1 naive HNSCC patients has led to a phase II study with enoblituzumab plus anti-PD-1 retifanlimab in PD-L1-expressing patients (96).