I think it's fair to say that maybe some point down the line, there might be a UK-U.S. trade agreement, but it's not going to happen anytime soon, because our focus is in negotiating with a big bloc, the European Union, to get a trade agreement done, and the UK is going to be in the back of the queue.
Remarks by the President Obama and Prime Minister Cameron in Joint Press Conference (22 April 2016). "Barack Obama: Brexit would put UK 'back of the queue' for trade talks", The Guardian.