Hala T. Borno, MD; Jennifer R. Rider, ScD, MPH; Christine M. Gunn, PhD A taxonomic revolution is occurring in medicine. Spurred by the halcyon vision of targeted “precision” therapy and enabled by access to massive electronic health data sets, high-throughput multichannel, molecular diagnostic assays, and advances in the understanding of disease biology, researchers have generated a plethora of new disease subclassifications (eTable and eFigure in the Supplement). Variably termed “phenotypes,” “endotypes,” or “subtypes,” these patient groups can share symptoms, biology, or prognosis and are proposed as the basis for precision care. The fast-paced research of SARS-CoV-2 has followed suit, with more than 60 subtypes proposed in the last year (eTable and eFigure in the Supplement). These subtypes range from simple classifications such as the