TGFB1 and head and neck squamous cell carcinoma: ESCC had a similar contribution of IS1 and IS2 compared to the HNSCC, but the most prominent signature observed in these tumors (36%) was IS3 (immune cold; low expression of genes related to inflammation, reactive stroma, T cells and IFN‐γ; high mutational burden; high TGF‐β signature).