CTLA4 and neoplasm: Inadequate infiltration of lymphocytes into tumor islets is often due to abnormal vasculature and chemokine gradients (43), as well as compensatory mechanisms like upregulating inhibitory immune checkpoint receptor signaling, including cytotoxic T-lymphocyte associated protein 4 (CTLA-4) and lymphocyte activation gene 3 (LAG-3) (44, 45).