Highly expressed FGF8 was positively correlated with the infiltration level of CD4 + T cells, CD8 + T cells, activated NK cells, macrophages M1, cancer-associated fibroblasts, and B cells; and was negatively correlated with the infiltration level of hematopoietic stem cells, neutrophil, resting NK cells and macrophages M0. Here, CD4 is linked to cancer.