It is entirely up to an actor if they want to star in a movie or not. In most cases, many celebrities turn down a role after reading the script, looking for a better opportunity, however, when Keanu Reeves did this, it kicked off his decade-long feud with 20th Century Fox.
Keanu Reeves

Something similar happened with actor Tom Cruise as his relationship with Paramount Studios was ruined after his public image took a hit in 2006, leading to his removal from the franchise after the third Mission: Impossible film, however its hard to imagine this franchise without Cruise, so with some efforts, Paramount brought him back and he gave a memorable performance in the fourth installment in the franchise, Mission: Impossible – Ghost Protocol.

20th Century Fox stopped working with Keanu Reeves after he turned down this movie

Sandra Bullock and Keanu Reeves in Speed (1994)
1994’s Speed was a massive success, making actor Keanu Reeves a well-known name around the world. With the box office success, 20th Century Fox was keen on creating a sequel, however, Reeves couldn’t understand and decided to turn it down. During his appearance on the Sunday Sitdown podcast, Keanu Reeves recalled,
“It was a tough decision, I really had an amazing time filming and making Speed. It did pretty well so there was a ‘Let’s do it again.’ Then I was doing a film at the time called Chain Reaction and I was in Chicago and I read the script. That film was pretty physical. It was a lot of running and cold. So they showed me the script and I just didn’t see it. I didn’t get it. So I couldn’t do it. I didn’t work at Fox for 15 years after that, I believe so, but I don’t know. It’s only a theory. I ended up working there again but it took 15 years.”
Fox did create a sequel called Speed 2: Cruise Control without Keanu Reeves, however, it was a massive failure. After more than a decade, Fox once again approached Keanu Reeves for the role of Klaatu in 2008’s The Day the Earth Stood Still.

Tom Cruise was also fired by Paramount Pictures

Tom Cruise
Back in 2006, actor Tom Cruise faced something similar not because he turned a role down, but because of his reputation. In 2006, Sumner Redstone, the then-chairman of Viacom (Paramount’s parent company), stated in an interview with The Wall Street Journal that the company was unhappy with Cruise’s conduct,
“We don’t think that someone who effectuates creative suicide and costs the company revenue should be on the lot […] His recent conduct has not been acceptable to Paramount… He had never behaved this way before, he really went over the top.”
The announcement came after the third Mission: Impossible film underperformed at the box office. Due to the actor’s connection with the Church of Scientology and his public relationship with Katie Holmes, Cruise’s popularity massively dipped.

So how did Cruise return to the franchise? The answer is J. J. Abrams. With efforts from the iconic director, Paramount agreed to hire Cruise for a fourth film, keeping a condition that they would keep another actor on hold side by side. In the end, the fourth installment, Mission: Impossible – Ghost Protocol broke the franchise’s box office record with a worldwide total of $694 million. Even today, the film is the second-highest-grossing film in the franchise.