Immune Induction Strategies to Improve Response to Immune Checkpoint Blockade in Triple Negative Breast Cancer (TNBC) Patients

Inclusion Criteria: * Metastatic or incurable locally advanced triple negative breast cancer (ER \< 10%, HER2 IHC 0,1+ or 2+ with no amplification) * Metastatic lesion accessible for histological biopsy * 18 years or older * Maximum of three lines of chemotherapy for metastatic disease and with evidence of progression of disease. Treatment with low-dose doxorubicin in the palliative setting is not allowed. * WHO performance status of 0 or 1 * Measurable or evaluable disease according to RECIST 1.1 * Disease Free Interval (defined as time between first diagnosis or locoregional recurrence and first metastasis) longer than 1 year * Subjects with brain metastases are eligible if these are not symptomatic and free of progression of at least 4 weeks * A maximum dosage of 360 mg/m2 of anthracyclines and no previous anthracycline-related cardiac toxicity. In case of radiation in the cardiac area, hypertension, diabetes mellitus or hypercholesterolemia, the left ventricular ejection fraction must be 50% or higher. * Adequate bone marrow, kidney and liver function Exclusion Criteria: * uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris * known history of leptomeningeal disease localization * history of having received other anticancer therapies within 2 weeks of start of the study drug * history of immunodeficiency, autoimmune disease, conditions requiring immunosuppression (\>10 mgl daily prednisone equivalents) or chronic infections. * prior treatment with immune checkpoint inhibitors. * active other cancer * history of uncontrolled serious medical or psychiatric illness * current pregnancy or breastfeeding