Ms. O’Donnell told colleagues that she had signed “a long-term commitment” to CBS News that will involve a new role that will include “big interviews.”

Norah O’Donnell, the “CBS Evening News” anchor since 2019, announced on Tuesday that she will step down from the anchor role after this fall’s presidential election.

Ms. O’Donnell told colleagues in an email that she has signed “a long-term commitment” to CBS News that will involve a new role that will include “big interviews.”

Wendy McMahon, the chief executive of CBS News, Stations and CBS Media Ventures, said on Tuesday that the network would remain “committed” to the “CBS Evening News” and that she would share more on the network’s plans for a replacement soon.

This is the latest move for a network confronting a wave of change. Ingrid Ciprian-Matthews, the former president of the news division, said earlier this month that she would step down from the position. CBS is about to undergo a wave of layoffs. And Paramount, the CBS News parent, is in the midst of a merger with Skydance.

This is a developing news story. Check back for updates.