The results showed that ATP6AP1 expression levels were significantly related to most checkpoint molecules, including TNFRSF8, CD40, PDCD1, TNFRSF18, TNFRSF25, TNFRSF4, TNFRSF14, VSIR, CD276, VTCN1, and BTLA in CRC. The gene discussed is PDCD1; the disease is colorectal carcinoma.