Co-cultures of organoids and immune cells have already been reported for several types of cancer, including gastric cancer organoids co-cultured with autologous CD8+ T cells and dendritic cells [17], pancreatic cancer with allogeneic T cells [18], autologous peripheral blood mononuclear cells (PBMCs) [19], and autologous CD8+ T cells and dendritic cells [20], rectal cancer with autologous tumour-infiltrating lymphocytes (TILs) [21], and non-small cell lung cancer and colorectal cancer co-cultured with T cells [22]. Here, CD8A is linked to gastric cancer.