FireCloud is a Broad Institute project funded by NCI to empower cancer researchers to access data, run analysis tools and collaborate securely in the cloud. It is powered by Terra, a secure, scalable cloud-native platform developed by the Broad Institute, Microsoft, and Verily, an Alphabet company. FireCloud provides access to many large NCI-funded datasets including TARGET and TCGA, complemented by a rich collection of other datasets and collaborative projects that are part of the Terra ecosystem, including the Human Cell Atlas, the All of Us Research Program, the AnVIL, and many others. Through FireCloud, researchers can leverage the powerful data analysis functionalities offered by Terra, including its scalable workflow execution system that can handle vast amounts of data processing through automated pipelines, as well as its highly flexible system of customizable cloud environments for interactive analysis and data visualization through preinstalled applications such as Jupyter Notebooks, RStudio, Galaxy, and IGV, and analysis frameworks such as Bioconductor and Hail. The platform offers access to a wide array of publicly available data analysis workflows and notebooks, many of which are available in fully loaded workspaces that include appropriate example data to demonstrate usage and ensure computational reproducibility. Researchers can also import their own tools, as well as community-sourced tools, through connected repositories operated by other collaborating organizations, such as Dockstore.