PDCD1 and breast carcinoma: Examples of these refinements include incorporating carboplatin for TNBC [20], combining pertuzumab with trastuzumab for HER2-positive breast cancer [21], and more recently, integrating immunotherapy in the form of programmed cell death protein 1 (PD-1) or ligand PD-L1 inhibitors into treatment regimens for early TNBC [22].