With the United States boycotting the G2, leaders from other nations sought to strike new deals, and some took a tougher tone with President Trump. President Cyril Ramaphosa of South Africa opened the summit’s plenary session on Saturday, signaling a shift in the global diplomatic landscape. The absence of U.S. President Donald Trump marked a pivotal moment for the G20, as leaders from major economies aimed to address pressing global challenges without American involvement.