CTLA4 and cancer: Inhibition of the programmed death pathway (PD-1/PD-L1 inhibitors; e.g., pembrolizumab, nivolumab, atezolizumab, avelumab, durvalumab, cemiplimab) or cytotoxic T-lymphocyte-associated protein 4 (CTLA-4 inhibitors; e.g., ipilimumab and tremelimumab) have revolutionized the approach to many types of cancer, with a growing number of indications annually [1,2,3,4,5,6].