Sakura heals Kankurou when he is poisoned by Sasori. Before the start of the Fourth Great Ninja War, Sakura explains to Kankuro how Sasori fights just in case Kankuro runs into him.
Among the Fans
Although KankuSaku isn't a very well-known pairing as the two characters didn't really have any interactions, it still has a few amount of followers. Those who do support it likely do so because of the fact that Sakura had cured Kankuro of his poison. One could argue that he has yet to formally thank her, which could lead to something more. Their rival couples are SasuSaku, NaruSaku, and LeeSaku.