This study is a Phase II trial evaluating the safety and efficacy of IBI343 in combination with chemotherapy as neoadjuvant therapy for subjects with borderline resectable pancreatic cancer (BRPC). The study enrolls treatment-naïve subjects with CLDN18.2-positive BRPC, confirmed by imaging and pathological diagnosis. Subjects will receive 4 cycles of neoadjuvant therapy. During or after neoadjuvant therapy, subjects who are unable to undergo radical surgical resection due to disease progression or other reasons will discontinue study treatment. After imaging assessment, subjects deemed eligible for radical resection by a multidisciplinary team (MDT) will undergo radical surgery 14-28 days after the last dose of neoadjuvant therapy . Following surgery, subjects will receive adjuvant therapy with the AG regimen or investigator-selected adjuvant chemotherapy. Adjuvant therapy will begin 21-56 days post-surgery, and the total duration of preoperative neoadjuvant and postoperative adjuvant therapy will be 6 months. Subjects will continue adjuvant therapy until the planned treatment duration is completed, or until disease recurrence, intolerable toxicity, withdrawal of informed consent, loss to follow-up, death, or other treatment discontinuation criteria are met (whichever occurs first). After discontinuation of study treatment, subjects will undergo safety follow-up and survival follow-up.