used to talk about how much sb/sth is connected with sb/sth :
Her job has something to do with computers.
'How much do you earn?' 'What's it got to do with you?'
Hard work has a lot to do with (= is an important reason for) her success.
We don't have very much to do with our neighbours (= we do not speak to them very often) .
I'd have nothing to do with him, if I were you.