As of September 28, 2020, Twenty-First Century Fox will no longer be a part of the Fox Corporation. The Walt Disney Company acquired most of 21st Century Fox in March 2019, and now only the following assets remain with Fox Corporation: the FOX broadcast network, FOX News Channel, FOX Business Network, FS1, FS2, Big Ten Network and the FOX Sports regional networks.
The decision to sell off 21st Century Fox was made by Rupert Murdoch and his son Lachlan Murdoch. At the time, it was seen as a way to focus on the more profitable news and sports businesses while also freeing up cash to invest elsewhere. The sale also included divestitures that were required by antitrust regulators in order for the deal to go through.
Now that 21st Century Fox is no longer part of the company, there are some changes being made at FOX. The biggest change is that TNF is moving from FOX to ESPN. This is because ESPN is owned by Disney (which also owns ABC). So when Disney acquired 21st Century Fox, they also acquired the rights to TNF.
Some people are upset about this change because they feel like FOX did a great job with TNF and they don't want it to move to ESPN. Others are excited about it because they think ESPN will do a better job with TNF than FOX did. And then there are those who don't really care either way - they'll watch whatever network airs TNF regardless of who owns it or where it's located.