CD274 and metastatic neoplasm: The retrospective pooled analysis of patients with recurrent or metastatic disease treated with pembrolizumab from both studies (KEYNOTE-028, KEYNOTE-158) showed that 88% of responsive patients had PD-L1 positive tumors, with a promising objective response rate of 19.3% and a durable anti-tumor activity, implying a possible correlation between PD-L1 positivity and response [42].