CTLA4 and cancer: To date, there are seven immune checkpoint inhibitors have been approved by U.S. food and drug administration (FDA) for certain cancer treatment (melanoma, NSCLC, lymphoma, urothelial carcinoma, etc.), including CTLA-4 inhibitors (Ipilimumab), PD-1 inhibitors (Pembrolizumab, Nivolumab, Cymplimab), PD-L1 inhibitors (Atezolizumab, Avelumab and Durvalumab) (Naimi et al., 2022).