HAVCR2 and head and neck squamous cell carcinoma: Other important ICIs include T-cell immunoglobulin mucin-3 (TIM-3), lymphocyte activation gene 3 (LAG-3), and V domain Ig suppressor of T-cell activation (VISTA), and TIGIT (T-cell immunoglobulin and ITIM domain) and Siglec-15 have shown their applications in advanced malignancy such as melanoma, NSCLC, and HNSCC [62,63,64].