You may be split on this, but The Big Bang Theory is ending after the show's 12th season which is set to premiere on September 24th!
According to EW the show is ending because Jim Parsons, who plays Dr. Sheldon Cooper on the show, is ready to leave the show. Without him the show would be greatly affected because he is one of the main characters.
The show's final episode will air in May 2019 bringing its total episode count to 279 episodes.
Honestly, I think a lot of people, including myself, are glad the show is ending because it kind of gave a bad reputation to nerds and also stereotyped what it was like to be a nerd or geek in the present age before nerd and geek culture became pop culture.
Now if only CBS could bring Star Trek: Discovery to prime-time and not their app!