From his Wikipedia page:
Justin Amash is an American lawyer and politician who served as the U.S. representative for Michigan's 3rd congressional district from 2011 to 2021. Originally a member of the Republican Party, Amash became an independent in July 2019 before joining the Libertarian Party in April 2020, becoming the first and only Libertarian Party congressman to date. Amash did not run for reelection in 2020.