In this review, we discussed several key sarcoma subtypes characterized by hallmark fusion proteins—such as Ewing sarcoma with EWSR1–FLI1/ERG, epithelioid hemangioendothelioma with WWTR1–CAMTA1/YAP1–TFE1 fusion—and highlighted their clinical implications as targets for therapy. The gene discussed is YAP1; the disease is Ewing sarcoma.