CNN President Jeff Zucker plans to step down when his contract expires at the end of the year, ending his tenure atop the cable news channel as it tries to hold onto ratings gains from a busy news cycle.

Zucker told staff about his plans in a morning meeting Thursday, according to CNN.

The longtime broadcast executive has been president of CNN since 2013. He is also chairman of news and sports for WarnerMedia, which is owned by AT&T.

Zucker, 55, led the network through President Donald Trump’s four tumultuous years, achieving recent viewership increases during a bitterly contested election and a mob attack on the U.S. Capitol on Jan. 6. That day was the most-watched in CNN’s history, and the network ended January as the most-watched cable news network, notching a rare victory over Fox News.

Despite that win for January overall, CNN’s viewership started to decline at the end of the month, and an expected slowdown in the news cycle during the Biden years will force Zucker to adjust the network’s strategy once again to keep viewers engaged.

After taking over the top job, Zucker reportedly wanted to make the network more personality-driven, and CNN anchors like Don Lemon, Anderson Cooper and Chris Cuomo have since become household names. Under Zucker, CNN has tried to portray itself as a source for straight news and distinguish itself between Comcast’s left-leaning MSNBC and the right-leaning Fox News, adopting the slogan “facts first” in a marketing campaign.

But while covering the story, the network has also at times become part of the story, namely when Trump frequently denounced CNN as “fake news.” During a single week last year, one of CNN’s reporters was arrested while on camera, demonstrators descended on the network’s Atlanta offices, and its anchors clashed with the president.

Zucker himself became the subject of scorn from Trump, who had suggested before that his job at CNN was in jeopardy.

Zucker didn’t reveal what he plans to do after this year. Last year, the executive suggested to the New York Times that he might run for mayor of New York. (The comments were in jest, a person close to Zucker later said, and he didn’t actually plan to run.)

—Bloomberg News