PD-L1 is expressed by tumor-infiltrating leukocytes (TILs) in the tumor microenvironment and by tumor cells themselves as an adaptation to evade anti-tumor immune responses.14,15 Multiple studies showed that approximately half of TNBC express PD-L1, predominantly in TILs rather than tumor cells.1,15-18. The gene discussed is CD274; the disease is neoplasm.