Pandemic Response and Emergency Preparedness Act of 2020 or the PREP Act of 2020 This bill authorizes the President to provide additional federal assistance following a major disaster emergency declaration related to a public health emergency, including a pandemic or virus threat, that occurs between the date of this bill's enactment and September 30, 2021. Such additional assistance includes unemployment assistance and lost wages, food assistance for low-income people from Department of Agriculture surplus commodities, legal services, crisis counseling assistance and training, and case management services.