BACKGROUND Gastric cancer (GC) poses significant treatment challenges due to late-stage diagnosis and the limited efficacy of conventional therapies. Immunotherapy, particularly immune checkpoint inhibitors such as pembrolizumab and nivolumab targeting the programmed death-ligand 1 (PD-L1) pathway, has shown promising results. Pembrolizumab is effective in PD-L1-positive tumors, while nivolumab improves overall survival and progression-free survival. Emerging therapies, including cancer vaccines