We found that Rap1b expression had significant correlation with infiltrating levels of B cells in 21 types of cancer, CD4 + T cells in 18 types of cancer, CD8 + T cells in 24 types of cancer, neutrophil in 27 types of cancer, macrophage in 26 types of cancer and dendritic in 26 types of cancer. The gene discussed is CD8A; the disease is cancer.