CTLA4 and head and neck squamous cell carcinoma: More clinical trials are currently recruiting HNSCC patients using Iplimumab, another anti-CTLA4 agent, and targeting other immune checkpoint proteins such as lymphocyte activation gene 3 (LAG-3) and mucin domain-containing protein 3 (TIM-3), all of which can potentially aid in the inhibition of the main PDL-1 pathway [42].