Rent and Mortgage Cancellation Act of 2020 This bill provides housing assistance during the COVID-19 (i.e., coronavirus disease 2019) public health emergency. Specifically, the bill suspends rental and mortgage payments for primary residences for a period lasting until 30 days after the termination of the federal emergency declaration relating to COVID-19. The Department of Housing and Urban Development (HUD) must establish funds to reimburse lessors and lenders for payments suspended under the bill. In addition, HUD must establish an Affordable Housing Acquisition Fund to support the acquisition of multifamily housing projects by nonprofit organizations, public housing agencies, cooperative housing associations, community land trusts, and state and local governments. For a five-year period, entities that are approved for such assistance shall be provided the first right of purchase with respect to such projects.