The feasibility and safety assessment of combining nivolumab and ipilimumab, a CTLA-4 inhibitor, with concurrent RT in patients with high risk LA-HNSCC was assessed in a single institution clinical trial (n = 24) [60], and early results showed 22% soft tissue ulceration at 3 months post-RT. This evidence concerns the gene CTLA4 and head and neck squamous cell carcinoma.