It shouldn't surprise you that it's Norah O'Donnell of CBS, whose 6:30 PM newscast has remained for years in 3rd place behind both NBC Nightly News With Lester Holt and ABC Evening News With David Muir. She's been in that role since July 2019. 

O'Donnell will now concentrate on in-depth interviews with major newsmakers and will turn up on the network's flagship and veteran "60 Minutes." Her tenure officially ends after the November U.S. Presidential election. 

It's sad to see what's become of CBS News. The network that once gave us Walter Cronkite and Edward R. Murrow is a shadow of its former self, and has been languishing in the ratings for decades. 

Still, it's rare for this high profile position to come open (Buffalo's Jeff Glor once occupied the role, but he didn't last long, either.)

No word on a replacement, although there are several candidates. But if you're not a CBS Evening News watcher, you may not have heard of any of them. 

"Among those who could be viewed as potential replacements are Margaret Brennan, the “Face The Nation” moderator, or Major Garrett, the Washington correspondent both of whom sometimes fill in when O’Donnell is off or on assignment; James Brown, the “NFL Today” moderator and CBS News special correspondent, who also fills in on occasion; or weekend anchors Jericka Duncan or Adriana Diaz."

Norah O’Donnell to Exit as ‘CBS Evening News’ Anchor to Become Senior Correspondent