<p dir="ltr">These supporting data underpin the study titled “IDO as Immunosuppressive Biomarker in Non-small Cell Lung Cancer: From Bedside to Benchside and Back.” They comprise:</p><ol><li><b>PBMC single-cell RNA-seq:</b> Compressed barcodes, feature lists, and expression matrices for peripheral blood mononuclear cells, enabling high-resolution profiling of the systemic tumor immune environment.</li><li><b>Human flow cytometry (FCS files):</b> Peripheral blood immune‐phenotyping data from NSCLC patients, used to quantify lymphocyte subsets and checkpoint marker expression.</li><li><b>Clinical cohort (n = 560):</b> De-identified records of NSCLC patients treated with PD-1/PD-L1 inhibitors, annotated with demographics, comorbidity scores, treatment timelines (ICI, chemotherapy, NSAIDs vs. acetaminophen), and survival outcomes.</li><li><b>Murine flow cytometry (FCS files):</b> Peripheral blood immune‐phenotyping data from lung tumor-bearing mice treated with ICI and analgesics support preclinical validation of clinical findings.</li></ol><p dir="ltr">Together, these multimodal datasets facilitate identification and validation of IDO-associated mechanisms and biomarkers that drive immune suppression and therapeutic resistance in NSCLC.</p>