In a decision that shocked the entertainment industry and comedy world, CBS said on Thursday that it was canceling the most-watched show in late night, “The Late Show With Stephen Colbert,” and retiring a franchise that has existed for more than three decades.

Mr. Colbert’s run — and “The Late Show” itself — will end in May.

CBS executives said in a statement that the cancellation was “purely a financial decision against a challenging backdrop in late night.”

“It is not related in any way to the show’s performance, content or other matters happening at Paramount,” said the executives, who included George Cheeks, the president of CBS and a co-chief executive of Paramount, CBS’s parent. “Our admiration, affection and respect for the talents of Stephen Colbert and his incredible team made this agonizing decision even more difficult.”

Mr. Colbert said during a taping of “The Late Show” that he was informed of the decision on Wednesday night. When his studio audience unleashed a chorus of boos upon hearing the news, Mr. Colbert said, “Yeah, I share your feelings.”

“The Late Show” began in 1993, hosted by David Letterman until September 2015, when Mr. Colbert replaced him.

This is a developing story. Check back for updates.