"Indo-European" is a Co-opting term used by Western media to promote a Euro-superior race ( Ahem google the term "Aryan" ) which has previously led to disastrous results.

We need a much more nuanced and much more finer detailed investigations into how languages evolved and human migration, evolution, in-habitation, inter-settlement commerce and local developments happened simultaneously and while influence from both cultures existed it was not "co-opted" or "superior vs inferior" but much more natural , indigenous and SHARED but NOT subsumed by each other.