The record is pretty bad for Canadian companies using ISDS to challenge U.S. policies. They've never won a case. I think that probably says something about how it works going up against a country as powerful as the United States. There are many opportunities, many means that Canadian companies have to assert their rights under U.S. law, their rights to do business in the United States, which are extensive. The U.S. legal system is one of the most established and elaborate in the world with respect to protecting private property. I don't think Canadian businesses are under any threat operating in the United States without ISDS.
On February 25th, 2020. See this statement in context.