The goal of CRISPR genome editing is to generate a cell line or animal model with one or more specific genetic modifications such as a gene knockout, introduction of a specific mutation, or knock-in of a gene or other sequence. These engineered cell lines serve as valuable research models. For example, by introducing mutations that are frequently found in cancers, researchers can create isogenic cell lines for functional genomic and compound screens to identify new drug targets or candidate compounds for new treatment strategies. Other examples of models generated by CRISPR genome editing include introduction of fluorescent reporters in the endogenous locus of a gene of interest or an inducible-degron that provides the researcher with a powerful and controlled system to study the function of a gene of interest.