Our findings showed that FNDC3B was strongly positively correlated with immune infiltration in LGG and GBM among all cancer types in the database, especially in the cytotoxic T cells and anti-tumor associated immune cells, such as central memory CD8 T cell, effector memory CD8 T cell, central memory CD4 T cell, regulatory T cell (Treg), natural killer cell (NK), natural killer T cell (NKT), memory B cell, and macrophage. The gene discussed is CD4; the disease is glioblastoma.