In the present work, we found that DDX21 expression was positively correlated with CAF and CD8+ filtering in several tumor types, such as ACC, BRCA-LumA, CESC, COAD, GBM, HNSC (HPV+/−), KIRP, LIHC, LUAD, LUSC, MESO, OV, PAAD, and THYM. This evidence concerns the gene CD8A and neoplasm.