The NAACP Legal Defense and Educational Fund filed a lawsuit under the Freedom of Information Act to compel the Department of Justice to release documents related to its request to add a citizenship question to the 2020 Census. This case is pending in the U.S. District Court for the Southern District of New York.
https://www.brennancenter.org/our-work/court-cases/naacp-legal-defense-and-educational-fund-v-united-states-dept-justice