They were indians who lived a long time ago. They became extinct a long time ago too.
Well, there's countless that they did have in common. To get to the point, though, they were both South Asian civilizations of antiquity, and even traded with each other a lot, as their respective coins have been found far away from where they would have been minted. They ahead of their times, as is evidenced by their mathematical, philosophical, cultural, political, and architectural splendor, and if you look around them there's mostly just nomads surrounding (nomads who tended to attack the wealthier sedentary communities). So they were both also islands of civilization in their areas, for the most part. Of course, Egypt was the Mesopotamians' neighbor to the southwest, but then there were deserts and some miles of distance separating them...