Dickerson shared the news in an Instagram post on Monday, Oct. 27.

CBS Evening News co-host John Dickerson is leaving at the end of the year amid a push from the network’s new editor-in-chief to replace its on-air talent with Fox News personalities.

His looming exit also represents the first high-profile talent exit from the network since media mogul David Ellison became parent company Paramount’s chairman following this past summer’s politicall...