Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA, USA. Breast Oncology Program, Dana-Farber/Brigham and Women's Cancer Center, Boston, MA, USA. Breast Tumor Immunology Laboratory, Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA. Division of Breast Surgery, Department of Surgery, Brigham and Women's Hospital, Boston, MA, USA. Ludwig Center for Cancer Research at Harvard, Harvard Medical School, Boston, MA, USA. Oncology Center, Hospital Sírio-Libanês, Brasília, Brazil. Division of Biostatistics, Department of Data Sciences, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. Center for Immuno-Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA. Medical Oncology Department, INSERM Unit 981, Molecular Predictors and New Targets in Oncology, Institut Gustave Roussy, Villejuif, France. Harvard Graduate Program in Biophysics, Boston, MA, USA. Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, MA, USA. Breast Cancer, Cancer Center, Massachusetts General Hospital, Boston, MA, USA. Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. eliezerm_vanallen@dfci.harvard.edu. Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA, USA. eliezerm_vanallen@dfci.harvard.edu. Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA. sara_tolaney@dfci.harvard.edu. Breast Oncology Program, Dana-Farber/Brigham and Women's Cancer Center, Boston, MA, USA. sara_tolaney@dfci.harvard.edu.