Hereby, we exploited an orthotopic clinically relevant model of PDAC to perform an in vivo CD8+ T cell screening and collected, together with the primary tumour, also the metastatic sites (peritoneal metastasis, liver and lung) and lymphoid organs, aiming to uncover targets conferring an improved T cell persistence and fitness also in the metastatic niches. The gene discussed is CD8A; the disease is neoplasm.