A Multicenter, Open-label, Phase II Umbrella Study to Evaluate the Efficacy and Safety of the Investigational Product in Participants With Advanced or Metastatic Pancreatic Cancer

Inclusion Criteria: * Age ≥ 18 and ≤ 75 years at the time of signing the informed consent form. * Histologically or cytologically confirmed advanced or metastatic pancreatic cancer. * Subjects with at least one measurable lesion assessed by the investigator according to RECIST v1.1. * Eastern Cooperative Oncology Group (ECOG) performance status of 0-1 within 7 days before the first dose. * Participants who have adequate bone marrow, liver, kidney, and coagulation function. * Male and female participants must agree to use highly effective methods of contraception during the specified period of the study. * Participants must voluntarily join this study, sign the informed consent form (ICF), and be able to comply with the visits and related procedures specified in the protocol. Exclusion Criteria: * History or current metastases to central nervous system. * Histologically or cytologically confirmed other pathological types or differentiation combined with other pathological types. * Subjects with other malignant tumors within 3 years prior to the first dose. * Presence of any cardiovascular and cerebrovascular disorders or risk factors. * Presence of uncontrolled systemic disease. * Presence of clinically symptomatic or uncontrolled pleural effusion, pericardial effusion, or ascites requiring repeated drainage. * History of interstitial lung disease (ILD) or non-infectious pneumonitis. * Presence within 3 months before the first dose of other moderate to severe lung disorders. * Tumor invasion or compression of surrounding vital organs and major blood vessels. * Active severe digestive system diseases. * Unresolved toxicity from prior anti-tumor therapy. * Serious infection within 4 weeks before the first dose. * Presence of active HIV, hepatitis B or hepatitis C or co-infection with HBV and HCV. * Known history of allogeneic organ transplant or hematopoietic stem cell transplant. * History of allergy to any component of the study drug or severe hypersensitivity to other monoclonal antibodies. * Participants who have undergone major surgery or had severe trauma within 4 weeks before the first dose, or are expected to require major surgery during the study. * Participants who have received other investigational drug treatments within 4 weeks before the first dose. * Pregnant or breastfeeding women. * Known history of psychosis or drug abuse that prevents the participant from cooperating with the study. * Have local or systemic diseases caused by non-malignant tumors, or diseases or symptoms secondary to tumors, which may lead to higher medical risk and/or uncertainty in survival assessment, or may affect protocol compliance. * Any condition that, in the investigator's opinion, interferes with the evaluation of the investigational product, participant safety, or interpretation of study results, or any other condition that the investigator deems unsuitable for participation in this study.