The USA is next door to Canada so of course we are going to trade with them. NAFTA/CUSMA have lead to closer integration between our economies that has been mutually beneficial but we are still separate sovereign countries.
Currently CUSMA restricts new free trade agreements with "non-market" economies which singles out China. Canada does not have a free trade agreement with China. We've made a trade deal with them that opens up imports for a limited number of vehicles.