While many world leaders and top musicians will be taking the stage Thursday at the Global Citizen Festival in Hamburg, Germany, ahead of the G20 summit, President Donald Trump won’t be there…because he wasn’t invited. Canada’s Prime Minister Justin Trudeau, Argentina’s President Mauricio Macri, Norway’s Prime Minister Erna Solberg and other world leaders will gather for the event with the likes of Coldplay, Pharrell Williams, Shakira and Ellie Goulding, all with the hope of raising as much as $661 million from governments for dealing with international health, gender equality and education issues. A source familiar with the policy goals of...