As shown in Supplementary Figure S2, multifocal SI-NETs were pauci-immune neoplasms with only scattered tumor-infiltrating lymphocytes (mean T-cell density: 2% of the tumor area; mean B-cell density: <1% of the tumor area), almost all of the tumors were completely negative for PD-L1 with only one tumor showing microfocal positivity (<1% positive tumor cells). Here, CD274 is linked to neoplasm.