Abstract Recent immunotherapy studies have generated a diverse collection of datasets, covering different aspects of cancer immune evasion. However, to the best of our knowledge, there are no public tools that can systematically rank genes regarding their function on tumor immune evasion and comprehensively evaluate biomarkers across multiple clinical cohorts. Therefore, we presented the TIDE-E (evaluator) website for users to evaluate their gene sets across a large panel of data cohorts (http://tide.dfci.harvard.edu). The website integrated two categories of data resources, human clinical datasets from public immunotherapy studies, TCGA, PRECOG, and METABRIC databases, as well as functional genomics datasets from CRISPR screens in preclinical models. For a user-defined gene set, the web application can test its performance as immunotherapy response biomarkers across multiple clinical studies, and rank the gene members according to their relevance in promoting tumor immune evasion. Citation Format: Jingxin Fu, Wubing Zhang, Peng Jiang, Xiaole S. Liu. TIDE-E: an online evaluator of tumor immune-suppressive function of gene sets [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5118.