The narrative is that a student tweeted something critical about China, and the CCP pressured his advisor into dropping him.
The reality is that the student published a tweet that "depicted a comic character that had been altered and had stereotyped Chinese features, with yellow skin tone and slit eyes". This understandably was perceived as racist by a Chinese student in Canada, who complained to the advisor. The advisor agreed and dropped her racist-seeming doctoral student.
The CCP wasn't involved. Nobody cared about his criticism of China. It was his racist-looking tweet that got him dismissed.
Edit: But yes, the CCP can have a chilling effect on free speech. See the Blitzchung controversy. This article is just a non-story.