Neoadjuvant Adebrelimab and Chemotherapy in High-rish ER+/HER2- BC

Inclusion Criteria: * pathologically diagnosed as unilateral primary invasive breast cancer with a) cT1c-T2N1-3 or cT3-4N0-3, b) Tumor Grade 3 or Grade 2 with PR- or Ki67 \> 20%; * IHC ER expression ≥1%; IHC HER2 0 or 1+; IHC HER2 2+ and no amplification in FISH test; * At least one measurable lesion according to RECIST 1.1; * Available core needle biopsy samples for PD-L1 status testing; * ECOG 0 or 1 within 10 days prior to initiation of treatment; * Not currently pregnant or breastfeeding, agree to strict contraception during treatment and at least 6 months after last dose; * Intact hematologic, liver, renal and heart functions; * Signed written informed consent. Exclusion Criteria: * Bilateral invasive breast cancer or Stage IV breast cancer; * Severe heart disease; * Diagnosed as immune deficiency or receiving systemic steroid therapy or any form of immuno-suppressive therapy within 7 days prior to the first dose of treatment; * Had active autoimmune diseases requiring systemic therapy within the past 2 years; * Severe systemic infections or other serious medical conditions; * Other malignant tumors in the past 5 years, except for cured carcinoma in situ of the cervix and skin cancer without melanoma; * History of HIV infection; * Active HBV or HCV infection; * Known allergies or intolerance to the therapeutic drug or its excipients; * History of application of any immunotherapy targeting PD-1/PD-L1/T cell receptors; * Judged by the investigator to be unsuitable to participate in this study.