Thirteen studies [11, 13, 16, 18, 19, 21–28] investigated the relationship between PD-L1 and the following eight clinicopathological factors: sex (male vs. female), tumor differentiation (poor vs. well/moderate), pN stage (III+IV vs. I+II), TNM stage (III+IV vs. I+II), vascular invasion (yes vs. no), perineural invasion (yes vs. no), age (>60 vs. ≤60), and tumor size (>5 cm vs. ≤5 cm). The gene discussed is CD274; the disease is neoplasm.