CD274 and triple-negative breast carcinoma: In the KEYNOTE-355 trial, pembrolizumab combined with chemotherapy improved PFS compared with the placebo in patients with PD-L1-positive metastatic triple negative breast cancer (9.7 months vs. 5.6 months; HR, 0.65; 95% CI, 0.49 to 0.86; p = 0.0012), but no improvement in PFS was observed in patients with lower PD-L1 expression [218].