“This will be a planned partnership between United States Steel and Nippon Steel, which will create at least 70,000 jobs and add $14 billion dollars to the U.S. economy,” Trump wrote, adding that U. S. Steel's headquarters will remain in Pittsburgh. 

Additional details have been few since Trump made the announcement on 23 May, but U. S. Steel has issued a statement praising Trump's leadership. 

"President Trump is a bold leader and businessman who knows how to get the best deal for America, American workers and American manufacturing. U. S. Steel will remain American, and we will grow bigger and stronger through a partnership with Nippon Steel that brings massive investment, new technologies and thousands of jobs over the next four years," the company said. 

U. S. Steel and Nippon Steel have not commented further, but U.S. Sen. Dave McCormick, a Pennsylvania Republican, told CNBC on Tuesday that the government would, under a national security agreement, receive a "golden share," affording it a say in who is named to the U. S. Steel board. 

You can find more here and here.