The numbers of studies ≥2 showed the association of PD-L1 overexpression with poor OS in breast (HR = 1.98, 95% CI = 1.15–3.41, P = .014), urothelial (HR = 2.24, 95% CI = 1.61–3.12, P <.000), renal (HR = 3.30, 95% CI = 2.23–4.86, P <.000), and gastric cancers (HR = 1.56, 95% CI = 1.02–2.37, P = .040). This evidence concerns the gene CD274 and gastric cancer.