CTLA4 and cancer: While the TME is highly heterogeneous, depending on the cancer type and anatomical location of the tumor, common TME features include an acidic microenvironment due to an overactive metabolism, the presence of chronic inflammation leading to the recruitment of immunosuppressive cells, such as myeloid‐derived suppressor cells (MDSC) or regulatory T cells (Treg), as well as the upregulation of immune checkpoint receptors (e.g., PD‐L1, CTLA‐4) involved in the process of immunoediting.