**4.2. Immune checkpoint inhibitors**

Because we know more and more about the interaction of inflammatory cells with cancer cells, in future, immunotherapy might be introduced for the treatment of breast cancer. Cancer cells use many mechanisms to avoid immune responses. For instance, in the TNBC, cancer cells express the PD-1 antigen and its ligands on cell surface. These proteins induce T lymphocyte tolerance. Preclinical studies showed that blocking the activity of the PD-1/PD-L1 might be used as treatment for TNBC. Both anti PD-1 antibodies (pembrolizumab and nivolumab) and an anti-PD-L1 antibody (atezolizumab) showed promise in preclinical studies [32].
