It is the latest in a series of high-profile departures from President Trump’s team.
In a statement released by the White House, Mr Cohn said it had been “an honour to serve my country”.
Mr Cohn, a former president of the Goldman Sachs bank, helped Mr Trump push through his sweeping reforms on taxes.
However, rumours continued to swirl that Mr Cohn and the president were not close.
In August 2017, Mr Cohn criticised Mr Trump over his reaction to a far-right rally in Charlottesville, Virginia, saying the administration “can and must do better”.
BBC
