My son was diagnosed with both, autism first then ADHD. Is there some aspect you’re wondering about in particular?
For me, they seem very interwoven, so it’s hard to say what aspects come from ADHD or autism. I’d say overall, where I see what I think is autism at play is in rigidity (difficulty with change and transitions, love of routine) and social interactions (he would choose to play alone vs. with others most of the time, not very socially inclined, doesn’t have back and forth conversations.)
The ADHD manifests more in ability to concentrate on things that he finds boring, forgetfulness and emotional volatility. (Although that could also be related to autism).
I think they’re almost on the same spectrum though, so you might see a lot of overlap in the two.