As the expressions of MCU complex members were associated with the immune cell infiltration, and the expressions of immune checkpoint molecules, especially PD-1 (programmed cell death 1, also named as PDCD1), PD-L1 (programmed cell death ligand 1, also named as CD274) and CTLA-4 (cytotoxic T-lymphocyte-associated protein 4), were related with the responses to immunotherapy in COAD, we explored the correlationship between the expressions of MCU complex members and the immune checkpoint molecules. The gene discussed is PDCD1; the disease is colon adenocarcinoma.