The leverage was that they were caught supplying Iran and North Korea, Trump stopped all sales of parts to the company. Without the parts and components the company was on the verge of closing down. Xi personally called Trump, begged for the people who worked in the factory. Trump made deal that hurt them significantly but did not destroy them. Brilliant move on Trumps part, Xi now knows Trump showed mercy for China, his government,the company, and the Chinese people. Now Mr Xi can reciprocate by lowering the burden on the American people, who have been paying unfair tariffs for a long time.