Saturday on PBS News Weekend, world leaders and throngs of mourners bid a solemn farewell to Pope Francis, as Trump and Zelenskyy meet at the Vatican to discuss hopes for lasting peace. Then, how NIH staffing shortages and layoffs threaten to delay the rollout of a potential breakthrough in the fight against cancer. Plus, we explore the worldwide crisis affecting coral reefs. PBS News is supported by - https://www.pbs.org/newshour/about/funders