OncoKB, MSKCC's precision oncology knowledge base, is a partially FDA-recognized somatic variant database that contains information about the oncogenic and clinical implications of genomic alterations in cancer. Alteration- and tumor-type-specific therapeutic implications are classified using the OncoKB Levels of Evidence system which assigns clinical actionability to individual mutational events. OncoKB data is integrated into cBioPortal, annotates >12K MSK tumor patient sequencing reports annually, and can be programmatically accessed via its web API with an OncoKB license.