Jenner & Block LLP announced a Chicago and New York duo will lead the firm next year.Chicago’s Randall E. Mehrberg and New York’s Katya Jestin will serve as co-managing partners starting in January.Mehrberg and Jestin will succeed Terrence J. Truax, who has served as the firm’s managing partner since 2014. He will return to full-time practice.Over the course of almost 40 years in law, Mehrberg has used …