EC characterized by MSI-H or dMMR usually harbors a higher neoantigen load and increased CD3-positive, CD8-positive, and programmed death-1 (PD-1)-expressing tumor-infiltrating lymphocytes and programmed death ligand-1 (PD-L1)-expressing intraepithelial and peritumoral immune cells when compared to MSS ECs50. The gene discussed is CD274; the disease is neoplasm.