The only stuff that made it from the book into the movie are some of the aesthetics, Michelle's name, and her motivation to find her brother.
List of stuff down below of what the book had that the movie didn't have. Spoilers for people who haven't read the book. (Read the book it's great)
There is no AI.
All the robots are controlled by humans.
The USA had a civil war that was fought by drone pilots who wore older versions of Neurocasters which required them to use addictive drugs that also destroyed their ability to reproduce.
People who wear the Neurocasters too long meld into a digital hivemind.
Neurocasters keeps the mind alive as long as it is worn. It does not protect the body from harm.
Graphic description of someone's brain getting chunkified by an anti-matter round.
Michelle's bio parents didn't die in a car crash. Instead her father is unmentioned (if I recall correctly) and her mom was a veteran who died from a drug overdose after being abandoned by the government. (foster parents "died" due to the Neurocasters)
Michelle dyed her blonde hair black because she wanted to distance herself from the "popular" girls and to spite her foster mom (who Michelle beat over the head with a lunch tray after she mocked her for wanting to dye her hair). Kind of important to her character. They keep her blonde in the movie for some fucking reason.
Michelle had a girlfriend who broke up with her after a crazy priest converted her. Heartbreaking to read.
Michelle found her brother's body rotting away in a house while wearing a Neurocaster. Still alive and in control of Cosmo.
It is implied that she and him rowed out into the ocean in a kayak to be swallowed by the waves.
Cultist working for the hivemind hunting for her brother as well, possibly what Giancarlo Esposito's character was based on though I doubt it.