Our findings indicate that, although no significant differences were found in PD-L1 expression among Chinese SBC patients as a whole,, as well as between those with duodenum cancer and jejunum/ileum cancer subtypes, there was a higher proportion of dMMRMSIH and TMB levels in patients with jejunum/ileum cancer as compared to duodenum cancer (Fig. 5). Here, CD274 is linked to duodenum cancer.