CTLA4 and Obesity: Moreover, obesity elevates circulating IL‐6, granulocyte colony‐stimulating factor (G‐CSF), and granulocyte–macrophage colony‐stimulating factor (GM‐CSF), which in turn upregulate immune checkpoint molecules cytotoxic T‐lymphocyte antigen 4 (CTLA‐4) and PD‐L1, thereby further suppressing T‐cell cytotoxicity and amplifying tumor immune escape [161].