Unfortunately, in a multicentre, phase I, dose-escalation study (NCT02301130) of the immunological efficacy of the combination of KW-0761 with durvalumab (anti-PD-L1 mAb) or tremelimumab (anti-CTLA-4 mAb), mogamulizumab did not show significant efficacy in patients with advanced solid tumours, including HNSCC. Here, CTLA4 is linked to head and neck squamous cell carcinoma.