https://tvline.com/2021/12/16/law-and-order-revival-sam-waterston-cast-jack-mccoy-season-21/

Sam Waterston Returning for "Law & Order" Season 22
by Nellie Andreeva
June 7, 2022


Sam Waterston will continue as DA Jack McCoy on "Law & Order‘s" upcoming 22nd season on NBC.

In doing so, Waterston is extending his "Law & Order" run to 18 seasons to become the longest-tenured cast member on the mothership series.

https://deadline.com/2022/06/law-order-sam-waterston-return-season-22-jack-mccoy-nbc-1235039847/