The correlations between PD-1 expression and age, sex, tumor size, and tumor number showed less heterogeneity (I2 ≤ 50%), while the correlations between PDL-1 expression and age, sex, tumor size, alpha-fetoprotein (AFP), tumor multiplicity, HBV history, and TNM stage showed less heterogeneity among the studies (I2 ≤ 50%). Here, CD274 is linked to neoplasm.