Based on the heterogeneity test, it was appropriate to use random-effects model to calculate the combined MD and 95% CI, which were 8.60 (2.67–14.54), P = 0.004, indicating that there is a statistically significant difference between two groups, which explains that SFI combined with chemotherapy in the treatment of breast cancer can significantly improve the CD4+ expression level. Here, CD4 is linked to breast cancer.