RecruitingPhase 2Drug trialAtezolizumab and Chemotherapy Treatment as T-cell Activators in Metastatic Triple Negative Breast Cancer PatientsTriple-negative breast cancer (TNBC) is among the most aggressive and lethal types of breast cancer, and currently available therapies have an unsatisfactory impact on patients' survival. The primary aim of this clinical trial is to evaluate efficacy in terms of Overall Response Rate (ORR) of atezolizumab plus cyclophosphamide and vinorelbine in first line patients with unresectable locally advanced or metastatic TNBC patients, previously treated with anti-programmed cell death ligand-1 (PD-L1) or anti-programmed cell death-1 (PD-1) - containing regimens, in the neoadjuvant/adjuvant setting.