Trump and his attorneys attempted to argue that the President and his relatives were not subject to prosecution for private business dealings. Furthermore, his attorneys argued that "under the U.S. Constitution, a sitting President can’t be subjected to any criminal investigation except as part of an impeachment inquiry. The team’s argument was not merely that Trump can’t be hauled into court and prosecuted—a claim that now has the imprimatur of the U.S. Department of Justice—but that a President can’t be subjected to any type of “criminal process,” because it would “distract him from his constitutional duties.” What Trump's attorneys attempted to do was to say Trump could not be prosecuted nor could he be even investigated for any criminal wrongdoing. In short, he was above the law and did not have to turn over his tax returns.
"In dismissing a request from Trump’s lawyers for a preliminary injunction to prevent Cyrus Vance, the District Attorney for Manhattan, from getting hold of the tax returns, Marrero rejected their legal arguments in a long and, at times, impassioned ruling. “Bared to its core, the proposition the President advances reduces to the very notion that the Founders rejected at the inception of the Republic and that the Supreme Court has since unequivocally repudiated: that a constitutional domain exists in this country in which not only the President but, derivatively, relatives and persons and business entities associated with him in potentially unlawful private activities, are in fact above the law,” Marrero stated. “Because this Court finds aspects of such a doctrine repugnant to the nation’s governmental structure and constitutional values, and for the reasons further stated below, it ABSTAINS from adjudicating this dispute and DISMISSES the President’s suit.”
When Trump was just a businessman, he was sued frequently and often and either lost money or won the suit and continued doing what he was doing. Transactions mean that: who wins the most is a good deal.