It's unclear if the band will cancel the rest of its concert dates scheduled for July.
Queen, Green Day, Avril Lavigne, BTS and other artists also are nixing upcoming dates.
The Seattle rockers have stoked controversy with a poster depicting President Trump’s dead body in front of a burning White House.
The band endorsed Democratic Sen. Jon Tester at a Montana concert.
Letterman was inducting Pearl Jam into the Rock and Roll Hall of Fame.
The singer donated $10,000 to a family in need.