Cahill signed a minor league deal with the Chicago Cubs on August 18, 2015.
Cahill pitched in the 2015 National League Division Series against the St. Louis Cardinals and pitched a scoreless inning of relief.
 It was only the third time he was used in the 8th inning or beyond in 2015.

On December 14, 2015, Cahill re-signed with the Cubs on a one-year, $4.25 million contract.

Cahill was mostly in the bullpen in 2016, making 50 appearances, finishing the year 4–4 with a 2.74 ERA.
The Cubs finished the season with a 103–58 record for an NL Central pennant, and would eventually win the 2016 World Series.
Cahill did not make any postseason appearances, but still won a World Series ring for the first time in his career.
Cahill signed a minor league deal with the Chicago Cubs on August 18, 2015. Cahill pitched in the 2015 National League Division Series against the St. Louis Cardinals and pitched a scoreless inning of relief.  It was only the third time he was used in the 8th inning or beyond in 2015.
On December 14, 2015, Cahill re-signed with the Cubs on a one-year, $4.25 million contract.
Cahill was mostly in the bullpen in 2016, making 50 appearances, finishing the year 4–4 with a 2.74 ERA. The Cubs finished the season with a 103–58 record for an NL Central pennant, and would eventually win the 2016 World Series. Cahill did not make any postseason appearances, but still won a World Series ring for the first time in his career.
Trevor Cahill