Trump and Fox have sparred before. In February, Trump demanded that Fox apologize for using profanity after Fox said, "I'm not going to pay for that [expletive] wall." Trump insisted that Mexico would foot the bill for his proposed wall on the U.S.-Mexican border.
Fox did apologize for any offense, but asked Trump, "But what about the other way around?" He then invited Trump to Mexico shortly after, saying, "I think it's very important to invite Donald Trump to come to Mexico and to learn about the real Mexico."