CTU President Jesse Sharkey outlines his union’s contract demands in a press conference inside City Hall on Jan. 15, 2019. (WTTW News)

After more than three years as head of the CTU, Jesse Sharkey will be stepping down at the conclusion of his current term on June 30, he announced Wednesday.

Karen Lewis appears on “Chicago Tonight” in March 2016. (WTTW News)

The former chemistry teacher who went on to battle former Mayor Rahm Emanuel throughout her tenure as the head of the Chicago Teachers Union, and nearly ran for mayor herself, has died. She was 67 years old.

Karen Lewis appears on “Chicago Tonight” in March 2016.

As Chicago Public Schools teachers return to the classroom this week, many will have a new leader at the top of their union.

Karen Lewis appears on Chicago Tonight on Sept. 5, 2017.

The powerful head of the Chicago Teachers Union cited her ongoing battle with brain cancer as the reason for stepping down, according to a statement to the Chicago Tribune.

Karen Lewis appears on Chicago Tonight on Sept. 5, 2017.

Chicago Teachers Union President Karen Lewis reportedly told friends “the cancer is back” before undergoing surgery Wednesday.

Karen Lewis appears on “Chicago Tonight” on Sept. 5.

Recovering from what she describes as a “slight stroke,” Chicago Teacher’s Union President Karen Lewis on Tuesday revealed that she’s been in the hospital for the past week.

The head of the Chicago Teachers Union joins us with a report on the first day of school.

(Matt Masterson / Chicago Tonight)

The CTU president said interest payments on the latest CPS borrowing could instead be used to pay for three college counselors, three pre-K teachers or six special education assistants.

The leader of the powerful Chicago Teachers Union joins us to talk lawsuits and funding for schools.

Chicago parents on Monday called for an end to the finger-pointing between Gov. Bruce Rauner and Chicago Public Schools CEO Forrest Claypool, saying the sides need to find common ground to solve the district's ongoing financial issues.

Chicago Teachers Union President Karen Lewis spent an hour Wednesday afternoon lecturing students and taking questions on education policy at the University of Illinois-Chicago. (Chicago Tonight)

With labor negotiations finished and a new contract finalized, Chicago Teachers Union President Karen Lewis is now calling for an end to the “explosion” of charter school chain growth.

Chicago Public Schools released the first look at the agreement’s financial layout Wednesday morning, hours after more than 70 percent of Chicago Teachers Union members voted in favor of the contract.

Results from nearly 60 schools still need to be tallied and the union expects final numbers to be released to its House of Delegates on Wednesday.

CTU President Karen Lewis said she's confident the union's 28,000 members will approve a tentative labor agreement with Chicago Public Schools next week. (Matt Masterson / Chicago Tonight)

The union's full membership will vote to approve or reject the tentative agreement with CPS inside schools across the district next week.

The Chicago Teachers Union President talks about the union's tentative agreement with Chicago Public Schools.

CTU President Karen Lewis said negotiations between the two sides would continue over the weekend and through Columbus Day if necessary, but as of Friday afternoon, she had “nothing substantial” to report.