Overall, six studies comprising 586 advanced breast cancer patients received anti-PD-1/PD-L1 monotherapy agents were included in this meta-analysis (Nanda et al., 2016; Dirix et al., 2018; Rugo et al., 2018; Adams et al., 2019; Emens et al., 2019) (Table 1). Here, CD274 is linked to breast carcinoma.