What makes you think he would? He’s barely known inside of Michigan, let alone on the national stage.
Plenty of articles on the subject.
https://www.google.com/search?source=hp&ei=27nHXN3cGpCf_Qbshr3oCw&q=justin+amash+2020&btnK=Google+Search&oq=justin+amash+2020&gs_l=psy-ab.3..0j0i22i30.1003.4508..5097...0.0..0.315.2617.4j10j3j1......0....1..gws-wiz.....0..0i131.RFQeC1kgRo8