In HNSCC patients, two CTLA-4-targeting antibodies have been developed: ipilimumab (IgG1k mAb, also known as MDX-010, MDX-101 and BMS-734016) and tremelimumab (IgG2 mAb, previously known as ticilimumab or CP-675,206). This evidence concerns the gene CTLA4 and head and neck squamous cell carcinoma.