CD274 and neoplasm: Studies show that programmed death‐ligand 1 (PD‐L1) expression (by tumour cells, and not immune cells) is seen in 12–21% of primary BCs; is enriched in triple‐negative BC (19–33%); significantly correlates with ALN metastasis; and adversely affects survival 12, 13, 14, 15, 16.