CTLA4 and head and neck squamous cell carcinoma: It was reported that blockade of cytotoxic T lymphocyte-associated protein-4 (CTLA-4) stimulated CD8+ T cells and upregulated the expression of IFN-γ and TNF-α in the TME, which induced the STAT1/interferon regulatory factor 1 (IRF1) pathway to trigger pyroptosis in head and neck squamous cell carcinoma (HNSCC) (159).