The U.S. government is clear that airlines must refund passengers whose flights are cancelled. The European Union is clear on this too but airlines have ignored their rules. In fact, European airlines have offered refunds to Americans (or where itineraries touch the U.S.) but not for Europeans (travel that doesn’t touch the U.S.).
Canada had been clear that airlines do not have to refund passengers for cancelled flights. Fortunately they are backtracking from that position.