CD274 and malignant colon neoplasm: Pembrolizumab is a novel immune checkpoint inhibitor that blocks programmed cell death-ligand 1 (PD-L1) in colon cancer patients with micro-satellite instability-high (MSI-H) and shows a high objective response rate (33%), high clinical complete response (cCR) rate (3% to 8%), and long median overall survival (31.4 months) [4–8].