For instance, blocking Notch signaling with a γ‐secretase inhibitor reduced tumor burden in a mouse model of HNSCC and was associated with decreased tumor levels of myeloid‐derived suppressor cells, tumor‐associated macrophages, regulatory T cells, and immune checkpoint molecules (PD‐1, CTLA‐4, T cell immunoglobulin and mucin‐domain containing‐3, and LAG3) [10]. This evidence concerns the gene CTLA4 and neoplasm.