Here's how it works:
* En cambio: means "on the other hand" or "however"
* No: means "not"
Examples:
* "Ella estudia mucho, en cambio no aprueba los exámenes." (She studies a lot, but she doesn't pass the exams.)
* "Me gusta el café, en cambio no me gusta el té." (I like coffee, but I don't like tea.)
Essentially, it introduces a contrast or opposition.