It should have been opened in June but was delayed by Trump. Ambassador bridge owner paid money into Trump PAC. It’s all there in the article under History -> Delayed Opening.

In June, The Detroit News reported that invitations were being sent out for a ribbon-cutting ceremony on June 12, with the bridge open to the public shortly after.[96] On the day before the planned ceremony it was announced that the event had been cancelled and that the opening of the bridge was delayed indefinitely to “resolve any outstanding issues”.[97][98]. Carney said that the delay had been requested by the United States, and representatives for Trump stated that his position had not changed since February.[99]

The New York Times subsequently reported that billionaire Matthew Moroun (who owns the Ambassador Bridge) had lobbied the Trump administration prior to the announcement.[91][92] The ranking member of the United States House Oversight Committee, Robert Garcia, opened an investigation into Commerce Secretary Howard Lutnick’s earlier meeting with Moroun, sending Lutnick a letter requesting communications related to that meeting.[93] Filings released February 20 showed that Moroun donated US$1 million to MAGA Inc., a Trump-affiliated super PAC, less than a month before Trump’s announcement.[94][95]