The ratings may not have been an issue.
The cancellation of Luke Cage caught many Marvel fans off guard. The television show was one of five Netflix Marvel shows that existed within the MCU. Along with Daredevil, Jessica Jones, Iron Fist, and The Punisher, Cage helped protect the streets of New York at a much smaller level than the Avengers. Marvel and Netflix canceled Iron Fist last week, to the surprise of none. Although the second season was much better than the first, Iron Fist appeared doomed to fail. Luke Cage, on the other hand, had a successful first season and an entertaining second season. That's why when Marvel canceled the bulletproof hero, fans were in shock.
As reported byThe Hollywood Reporter, the reasons for the cancellation of Luke Cage came down to creative differences. It is unclear if those creative differences were between the showrunner Cheo Hodari Coker and Netflix, or between Netflix and Marvel. It's reported that the creative team and Netflix could not come to terms for a third season. Netflix does not release their viewership figures for their shows, but it doesn't appear that Luke Cage lacked support. A petition to get the show back on the air has surfaced, while fans on Twitter have been voicing their displeasure with the cancellation.