Can an immunotherapy combo boost tumor shrinkage in a common breast cancer?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

3.1 Inclusion Criteria Patients must meet all of the following criteria to be eligible: Age: ≥18 years old. Clinical-pathological confirmation: cT2-cT4 breast cancer, or cT1c with axillary lymph node metastasis. Histopathologically confirmed HR+/HER2- invasive breast cancer: ER and/or PR positive (IHC nuclear staining ≥1%). HER2-negative (IHC 0 or 1+ without FISH testing, or IHC 2+ with FISH-negative amplification). Ki67 ≥20%. Clinically measurable lesions: Measurable lesions confirmed by ultrasound, mammography, or MRI (optional) within 1 month prior to randomization. Adequate organ and bone marrow function (within 1 month prior to chemotherapy): Absolute neutrophil count (ANC) ≥2.0 × 10\^9/L. Hemoglobin ≥90 g/L. Platelet count ≥100 × 10\^9/L. Total bilirubin \<1.5 × ULN (upper limit of normal). Creatinine \<1.5 × ULN. AST/ALT \<1.5 × ULN. Cardiac function: Left ventricular ejection fraction (LVEF) ≥55% by echocardiography. Reproductive status: Women of childbearing potential must have a negative serum pregnancy test within 14 days prior to randomization. ECOG performance status: ≤1. Informed consent: Signed written informed consent. 3.2 Exclusion Criteria Patients meeting any of the following criteria will be excluded: Evidence of metastatic breast cancer: Chest/abdominal CT and bone scan required at any time from diagnosis to randomization to exclude metastasis. PET/CT may substitute for other imaging modalities. Prior systemic therapy: Chemotherapy, endocrine therapy, targeted therapy, or radiotherapy for the current breast cancer. Second primary malignancy, except: Adequately treated non-melanoma skin cancer. Prior immunotherapy: Treatment with anti-PD-1, anti-PD-L1, anti-PD-L2, or other immune checkpoint inhibitors. Immune-related conditions: Diagnosed immunodeficiency or active autoimmune disease. Severe cardiopulmonary disease: Uncontrolled or clinically significant. Active hepatitis: Hepatitis B or C with detectable viral load. Transplant history: Prior organ or bone marrow transplantation. Pregnancy or lactation: Pregnant or breastfeeding women. Other contraindications: Severe uncontrolled comorbidities deemed by investigators to contraindicate chemotherapy or PD-1 inhibitor therapy.