Cleary Gottlieb Steen & Hamilton antitrust attorney Mark Nelson will join T-Mobile as its newest general counsel in October, taking the reins from longtime GC Dave Miller, who will be retiring early next year, the company announced Thursday.

Miller, who has been with T-Mobile since 1995, will officially depart the company April 1, 2022, taking on an advisory role during the leadership transition after Nelson takes over the 550-person legal department Oct. 11.