Initial theories suggested that breast cancer (BC) is a non-immunogenic disease with fewer immunogenic tumour antigens [10], so BC has not been considered a cancer amenable to immunotherapeutic approaches for a long time; however, recent studies have shown evidence of significant immune cell infiltration of tumour-infiltrating lymphocytes (TILs) in a subset of patient tumours and a consolidated understanding that Triple Negative Breast Cancer (TNBC) is a highly heterogeneous breast cancer subtype, with higher expression levels of PD-L1 and more TILs. The gene discussed is CD274; the disease is breast carcinoma.