Mark Sanford withdrew from the Republican presidential race on November 13. Prior to that, the Michigan Secretary of State had determined that he is mentioned in news media and so had listed him on the 2020 Republican presidential primary ballot.
Even though the Michigan Secretary of State’s office is aware that Sanford withdrew, the state will not remove his name from the ballot unless he specifically asks the state to remove him by December 13. As of November 21, he has not bothered to communicate with the Michigan Secretary of State’s office about that. Sometimes presidential candidates who withdraw early in the process don’t exert the energy to contact states and ask them to remove their name.
Sanford’s name is not on the presidential primary ballot of any other state.