Herein, we used TIMER, EPIC, quanTIseq, xCell, MCP-counter, CIBERSORT and CIBERSORT-ABS algorithms to investigate the potential correlations between key gene expression and immune infiltration levels of neutrophils, CD4+ and CD8+ T cells in 1,100 breast cancer samples from TCGA through the TIMER 2.0 web server. The gene discussed is CD4; the disease is breast carcinoma.