XRCC4 expression was significantly correlated with infiltrating levels of memory CD4 + T cells in 19 types of cancers, Th1 CD4 + T cells in 12 types of cancers, Th2 CD4 + T cells in 20 types of cancers, CD8 + T cells in 15 types of cancers by TIMER, cancer associated fibroblast in 13 types of cancers by TIDE, M1 macrophages in 12 types of cancers by QUANTISEQ and M2 macrophages in 14 types of cancers by TIDE. The gene discussed is CD4; the disease is cancer.