Circulating tumor DNA (ctDNA) has been demonstrated to be an effective prognostic marker in breast cancer. Various studies have shown that early TNBC breast cancer patients with positive ctDNA have high risk of cancer recurrence and worse prognosis. This study aimed to identify TNBC patients with positive ctDNA and initiate boost therapy in these high risk patients.

Inclusion Criteria:

• Patient is ≥ 18 years-old at the time of consent to participate this trial
• Stage II - III primary triple negative breast cancer patients(TNBC), TNBC is defined as ER <=1%, PR <=1%；HER2 receptor IHC=1, or IHC=2 and FISH negative.
• positive ctDNA after curative surgery and/or adjuvant chemotherapy
• ECOG 0-2
• If indicated, patient agree to receive adjuvant radiotherapy according to the institutional guidelines
• Patient receives adjuvant chemotherapy according to the NCCN guidelines
• Patient has available tumor tissue from the surgical specimen for next generation sequencing(NCS)
• Patient agrees to give blood samples for ctDNA tests every 3 months in 5 years

Exclusion Criteria:

• Patient has previously received any PD1/PDL1 blockage treatment
• Pregnant or breast-feeding (lactating) women or women who plan to become pregnant or breast-feed during the trial
• Patient with distant metastases of breast cancer beyond regional lymph nodes (stage IV according to AJCC 8th edition)
• Patient participates another interventional clinical trial
• Patient has a concurrent invasive malignancy or a prior invasive malignancy whose treatment was completed within 3 years before randomization
• Patient with autoimmune disease preventing the use of camrelizumab
• Patient has any other concurrent severe and/or uncontrolled medical condition that would, in the Investigator's judgment, cause unacceptable safety risks, contraindicate patient participation in the clinical trial or compromise compliance with the protocol