Canada's Prime Minister Mark Carney waves next to U.S. President Donald Trump at the White House in Washington, D.C., U.S., Oct. 7, 2025. Evelyn Hockstein | ReutersThis is CNBC's Morning Squawk newsletter. Subscribe here to receive future editions in your inbox.Here are five key things investors need to know to start the trading day:1. Oh, CanadaPresident Donald Trump said late last night that he is ending all U.S. trade negotiations with Canada over an ad aired by Ontario's provincial government featuring ...