> Starting around 2015, paleogenomic studies revealed a dramatic genetic turnover across Europe around 3000 BCE. In many regions, 70-100% of male lineages were replaced within just a few centuries. The Yamnaya and their descendants didn't just rule; they moved in enormous numbers. The debate isn't fully settled, and both mechanisms likely operated in different places and times, but the DNA evidence has shifted the balance decisively toward mass migration as the primary driver in Europe.
They killed all the males and enslaved the women.
The first part of this is supported by an increasing number of archaeological finds. AFAIK the second part is not.