The results showed that the patients treated with combined therapy had a higher MD than those treated with chemotherapy alone (MD 1.57; CI: 0.32–2.81, p = 0.01; I2 = 43%) (Fig 4B), which explains that SFI combined with chemotherapy in the treatment of colorectal cancer had an advantage of increasing the percentage of helper CD8+ compared with control group. The gene discussed is CD8A; the disease is colorectal cancer.