Neurodivergence is the term for people whose brains function differently in one or more ways than is considered standard or typical, examples are: Autism, ADHD, Dyslexia, etc.
Neurodiversity is the idea that it's normal and acceptable for people to have brains that function differently from one another. Rather than thinking there is something wrong or problematic when some people don't operate similarly to others, neurodiversity embraces all differences.