CTLA4 and breast cancer: Among BC subtypes, the phenotype of PD-L1+CD45−CK+ was present in 41% of TNBC and 29% of luminal patients, while the phenotype of CTLA-4+CD45−CK+ was present in 36% of TNBC and 23% of luminal patients, implying that immunosuppressive phenotypes potentially predominate in TN breast cancer.