But his “I, Daniel Blake,” which won the Cannes Film Festival’s Palme d’Or, has powerfully struck a nerve, tapping into the same working-class frustrations that are upending politics in Europe and the U.S. The film, which opens in limited release in North America on Friday, has emerged as a kind of rallying cry, part film and part movement. It’s about a man – a cheery, blue-collar bloke – who, after a heart attack, is told by his doctor he’s too sick to work.