Cadonilimab Combined With Chemotherapy as First or Second Line Treatment in Recurrent or Metastatic Triple Negative Breast Cancer

Inclusion Criteria: * Recurrent or metastatic TNBC patients; * TNBC defined by immunohistochemistry as ER\<1%, PR\<1%, Her2=0\~1+, or 2+ while HER2 Fish test shows no amplification； * Previous received no or only first line chemotherapy treatment for recurrent or metastatic TNBC；When the time between cancer metastasis and the end of adjuvant chemotherapy exceeds 1 year, the systemic chemotherapy for metastasis treatment is recorded as first-line treatment; When less than 1year, the systemic chemotherapy for metastasis treatment is recorded as second-line treatment； * ages 18 to 75 years at the time of signing the informed consent form (ICF); * Eastern Cooperative Oncology Group (ECOG) performance status (PS) score of 0 or 1; * expected survival of ≥3 months; at least one measurable lesion per RECIST (version1.1); * acceptable renal and liver function; Exclusion Criteria: * They had received ICIs (i.e., anti-PD-1 antibodies, anti-PD-L1 antibodies, and anti-CTLA-4 antibodies.)； * Patients with active central nervous system (CNS) metastatic lesions or meningeal metastases； * Patients with an active autoimmune disease that requires systemic treatment in the past two years； * A known history of primary immunodeficiency； * Pregnant or lactating women； * Previous or current abnormalities of any disease, treatment, laboratory tests may confuse the study results, affect the subject's participation in the study