That may not be overruled, at least not quickly; I say this partly because I don't get the impression that the New York courts are especially well-disposed toward Trump, and the N.Y. Court of Appeals may decide to take their time while this and other suits go forward. If I read this Washington Post article correctly, there's already a US Supreme Court decision that says sitting presidents can be sued while they're in office. (Trump's attorney says they'll appeal on the basis that the Appellate Division misread that Supreme Court case.) I suspect the U.S. Supreme Court would be unlikely to take a further appeal from the New York Court of Appeals if that decision simply upheld this one

Possibly relevant: the highest court in New York state is called the Court of Appeals; the Appellate division is below that, and takes appeals from a variety of city and county courts with sometimes-confusing names (including "State Supreme Court," which is not a court of appeals). (This seemed weirder before I moved to Massachusetts, where the "general court" is our legislature and the highest court as usually understood is the "Supreme Judicial Court.")