Tonight on PBS News Weekend, world leaders and throngs of mourners bid a solemn farewell to Pope Francis, as President Trump and Volota Merzolinsky 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. And we explore the worldwide crisis affecting coral

reefs that scientists blame on global warming. It's very alarming. So I think people really need to recognize what they're doing,

you know, by the inaction. You are, it's the kiss of death for coral reefs. Good evening. I'm John Yang.

Pope Francis was laid to rest today after a solemn requiem mass outside St. Peter's Basilica in the Vatican.

Our coverage begins with special correspondent Malcolm Brabant in Rome.

Beneath an Azeo-Roman sky, a quarter of a million people crowned into St. Peter's Square

to glorify the former Argentinian nightclub bouncer, who history will remember as a Pope of Peace.

They came to participate in the grandest of funeral services with rituals dating back centuries.

They saw kings and princes and presidents take their places beneath a fierce April sun,

including William, the heir to the British throne.

The former US President Joe Biden and his wife Jill

slipped into the less hallowed seats

opposite the scarlet phalanx of cardinals,

who in May will be sequestered to choose the next pope.

Francis was universally acclaimed as an extraordinary pontiff.

And in keeping with his peace-loving spirit behind the scenes,

there was a significant attempt to broker a truce between Ukraine and its Russian invaders.

Before paying his respects at the coffin, President Trump sat down with Ukraine's President Zelensky

for the first time since their rancorous confrontation in the Oval Office two months ago.

Trump reportedly pressured Zelensky to accept a plan in which Ukraine will formally surrender territory occupied by Russia,

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