I think the link is that they share common root words to old words such as boat and suchlike, not that they are from the same roots generally.

This could point more to heavy trade links rather than a common cultural root. That said there are similarities in the art, dancing and music.

Basque is the only non IE language in Europe (with Hungarian and Finn, although these two are related to each other and belong to a well known family, unlike Basque which is likely a Paleolithic language of unknown origins)