She is the mayor of Toronto. Her late husband was the leader of the federal New Democrat Party (which is our farthest left party) from 2003-2011. She used his name and popularity to become a prominent politician in Toronto and just became Mayor a couple years ago.

She became mayor due to name recognition. The former mayor stepped down in disgrace after he was caught having an affair with one of his staffers. He was widely expected to get reelected so there wasn't any good and recognizable candidates so she swooped in and won.