Workforce Mobility Act of 2020 This bill prohibits employers from entering into, enforcing, or threatening to enforce noncompete agreements with employees, subject to exceptions. Noncompete agreements prohibit an employee from performing similar work or working with a competitor employer for a certain period of time or in a specified geographic area after the current working relationship terminates. Employers must post in the workplace a notice of this prohibition. The bill permits certain noncompete agreements in the context of the sale of a business or the dissolution of a business partnership. Violations of the prohibition against noncompete agreements are unfair business practices subject to enforcement by the Federal Trade Commission. The Department of Labor also must receive and investigate complaints of such violations and may bring claims to prohibit enforcement of such noncompete agreements and seek civil penalties.