Season two of the Expanse debuts on Syfy on February 1st and it continues to diverge from the original novel. The series stars Thomas Jane, Steven Strait and Shohreh Aghdashloo and is based on the novel Leviathan Wakes by James S. A. Corey (the pen name for Daniel Abraham and Ty Franck). I read the novel over the summer and many things that happen in the series didn't happen in the book. None of the story takes place on Earth or Mars and the character of Chrisjen Avasarala never comes up.
And at this point, they're only about half way through the book. It's part of a multi-novel series whose sixth book, Babylon's Ashes, just came out this week. So, as long as the series stays popular, they've got a lot of source material to work with along with whatever they add on their own.