CTLA4 and cancer: Some research also involves the broad‐spectrum targets, such as the epidermal growth factor receptor (EGFR),61, 85, 86 programmed cell death ligand‐1 (PD‐L1),87, 88 vascular endothelial growth factor (VEGF),89, 90 and cytotoxic T lymphocyte‐associated protein‐4 (CTLA‐4),91, 92 which are critical in the development and progression of various cancers.