As leaders from across the world gather for two major summits in South America in the coming days, the uncertainty brought by Donald Trump’s impending return to the White House is expected to loom large.

The meeting with President Xi Jinping comes as President-elect Donald J. Trump has promised a much more aggressive approach to China that includes vast tariffs on Chinese goods.

President Joe Biden is planning to meet Saturday with Chinese President Xi Jinping during a trip to Lima, Peru, according to White House officials, in what amounts to a final meeting between two leaders of superpowers amid a period of significant transition that could alter that relationship.