CTU will be disbanded by the government at the start of Season 7. Jack will be hauled in front of a Senate Committee to explain his actions over the past several seasons. The show, itself, will be set in Washington DC and not Los Angeles. [source]
Producers briefly toyed with the idea of making Tony the Big Bad of Season 7, but that plot was scrapped. The show recently reached out to Gary Oldman to play Day 7's evil genius. [source]
"It's The Sentinel meets Air Force One!"