Coronavirus TANF Expansion Act This bill reauthorizes through December 31, 2020, the Temporary Assistance for Needy Families (TANF) program and expands TANF eligibility and assistance to respond to the COVID-19 (i.e., coronavirus disease 2019) public health emergency. Specifically, states may (1) allow certain families that have incomes of up to 400% of the federal poverty level and that have experienced reduced incomes because of COVID-19 to receive TANF assistance, and (2) provide additional cash payments to these and other TANF recipients. The Department of Health and Human Services must increase state and tribal TANF grants to offset increased expenditures that result from these changes. The bill provides appropriations for this purpose. The bill also suspends TANF work requirements and other conditions during the emergency.