This study is for people with advanced pancreatic cancer to see if combining radiation with two medicines, envafolimab and capecitabine, is effective and safe. **Radiotherapy** is a treatment using high-energy rays to kill cancer cells. **Envafolimab** is a medicine that helps the immune system fight cancer, and **capecitabine** is a chemotherapy pill taken to stop cancer cells from growing. **Key Points:** - The study uses a special type of radiotherapy and involves taking medicine by injection and pill. - Participants must not have cancer spread beyond specific areas and should not have certain health conditions. - Participation involves regular hospital visits and treatments, and may continue until the cancer worsens or the patient cannot tolerate the treatment. **Eligibility:** People aged 18-90 with non-removable pancreatic cancer that hasn't spread significantly. Participants must have good organ function and be willing to follow study procedures. Those with certain health conditions or treatments are not eligible.