The Fairness Doctrine only applies to network television, which Fox News need not abide by.

The report by the Congressional Research Service notes that broadcast is "distinct from cable, satellite, and the Internet, which are all services for which consumers must pay.
“It does not appear that the Fairness Doctrine may be applied constitutionally to cable or satellite service providers,” it continues.

https://www.usatoday.com/story/news/factcheck/2020/11/28/fact-check-fairness-doctrine-applied-broadcast-licenses-not-cable/6439197002/