The Cancer Imaging Archive (TCIA) is a large online archive of medical images and associated clinical data from cancer patients. It contains a variety of imaging modalities like CT, MRI, and PET scans covering many cancer types. The archive aims to support precision medicine by linking imaging data to molecular and genomic data from sources like The Cancer Genome Atlas. It provides a growing collection of over 40,000 subjects and 70 datasets that are frequently used in research publications and challenge competitions. The TCIA helps relieve researchers of data sharing burdens and provides hosting, de-identification, and support services to submitters and users of the archive.