Their language is undeciphered, we don't know how much they influenced us in that regard. This also makes any cultural influence they may have had difficult to find.
What we can confirm is that they lived in modern day Pakistan/north-west Hindustan, and that they probably did influence the Aryan invaders to some degree as well as intermarry with them.
As for ancestry, as said before, almost everyone has ancestors from these ancient civilisations since they are from so long ago, so that point is almost irrelevant.