Meta-analysis indicated that there was a statistically significant difference between the two groups for CD8+ (MD: 4.96, 95% CI, 1.16–8.76, p = 0.01; Fig. 8a) and CD4+/CD8+ (MD: 2.58, 95% CI, 1.69–3.47, p < 0.00001; Fig. 8b), but not for CD4+ (MD: 12.09, 95% CI, − 0.34-24.52, p = 0.06; Fig. 8c), which indicated that XAPI combined with chemotherapy could enhance the immune function in NSCLC patients to some extent. This evidence concerns the gene CD4 and non-small cell lung carcinoma.