The role of immunotherapy in hormone receptor (HR)-positive, HER2-negative breast cancer is underexplored. 11 Immunology and Molecular Oncology Diagnostics, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy.10 Department of Pathology, Azienda Ospedale Università Padova, Padova, Italy.9 Clinical Research Unit, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy.8 UOSD Hereditary Tumors, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy.7 Department of Medical Oncology, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, Aviano, Italy.6 Department of Medicine and Surgery, University of Parma, Parma, Italy.5 Medical Oncology and Breast Unit, University Hospital of Parma, Parma, Italy.4 Department of Oncology and Advanced Technologies, Oncology Unit, Azienda USL-IRCCS, Reggio Emilia, Italy.3 Department of Surgery, Oncology and Gastroenterology, University of Padova, Padova, Italy.2 Medical Oncology 2, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy. 1 Department of Surgery, Oncology and Gastroenterology, University of Padova, Padova, Italy.