According to the TIMER2.0 results, we identified MUC4 expression has weak positive relevance with tumor purity and the immune-infiltrating levels of CD4+ T cells (R = 0.147, p = 1.55e-03) and B cells (R = 0.119, p = 1.07e-02) but a negative correlation with dendritic cells (R = −0.127, p = 6.19e-03) in KIRC. This evidence concerns the gene CD4 and neoplasm.