Conversation so far:
what did Epstein do for the Cubs?
The Cubs finished in last place in the National League Central for the first three years of Epstein's presidency.
when did Theo join the Cubs?
Two days later, the Cubs officially introduced Epstein as president of baseball operations.
what did Theo do for the cubs?
(positively)?
After a three-year, top-to-bottom rebuild, the Cubs clinched a playoff berth in 2015.

Question: did the cubs ever win the championship under THeo?
Self-contained rewrite: Did the Cubs ever win the championship under Theo?