CTLA4 and cancer: PD‐L1 and B7‐H3 are transmembrane protein ligands expressed on the surface of cancer cells which suppress T‐cell activity in the TME by binding to the immune cell receptors, programmed cell death receptor‐1 (PD‐1) and cytotoxic T‐lymphocyte‐associated protein‐4 (CTLA‐4), on T‐cells to transmit inhibitory signaling to disable effector T‐cells, enabling tumor immune escape and progression.36, 37, 38