TNFSF4 and neoplasm: Given that OX40/OX40L are less studied immune checkpoints and have yet to be fully explored, especially in PDAC, we investigated OX40 and OX40L expression and simultaneously detected the status of other biomarkers in the tumor immune microenvironment using multiplexed immunofluorescence (mIF), digital imaging techniques, immunohistochemistry, and next-generation sequencing (NGS) data in PDAC samples and analyzed their correlations with immune markers (CD3, CD8, Foxp3, PD-L1, B7-H3, and B7-H4), and clinicopathological features and outcomes.