This study is testing how well a medicine called pembrolizumab works when used with other treatments to fight a specific type of stomach cancer. Pembrolizumab is a special kind of medicine known as a monoclonal antibody, which helps the body attack cancer cells. Another medicine, capecitabine, is used to stop cancer cells from growing. Doctors also use radiation therapy, which involves high-energy rays, to kill cancer cells.

Key Points:

• The study includes multiple treatment courses and surgery, lasting several months.
• Participants will have regular follow-ups for up to four years after treatment.
• There may be risks of side effects, but the study aims to improve survival rates and understand safety.

To join, patients must have a specific type of stomach cancer and meet other health criteria. They cannot join if they've had certain previous treatments or health conditions. Men and women must use contraception to prevent pregnancy during the study. The study will check for the cancer's response to the treatments and any side effects experienced by the participants. It's important to understand both the potential benefits and risks before deciding to join the study.