From Cubs.com:

John McDonough ended his 24-year tenure with the Cubs, most recently serving as team president, to take over the NHL Chicago Blackhawks.

[...]

McDonough's long-term job status with the Cubs was uncertain because of the pending sale of Tribune Co. and the likely sale of the Cubs. He signed a multiyear contract with the Blackhawks. Whoever replaces McDonough will likely be on an interim basis until the new ownership is named.

Crane Kenney "will continue overseeing Cubs operations until the sale of the team is completed. General Manager Jim Hendry will continue to lead baseball operations," according to the press release.