CD8A and colorectal carcinoma: In the MR analysis of immune cells on CRC, the IVW results indicated that CD40 on monocytes, CD45 on CD33+HLA-DR+CD14-, terminally differentiated CD4+T cells, central memory CD4+T cells, and CD28 on CD28+CD45RA+CD8+T cells have a negative causal effect on CRC.