Various cultures around the world had slaves, including cultures in the ancient near east, like Egypt, Mesopotamia, Babylon, Assyria, etc. How slavery was practiced around the world varied with culture, most cultures have debt slavery where people sold themselves into slavery to pay off debts, and there were those who are made slaves by conquest. Some had chattel slavery where people were treated like animals and kidnapped, but when most people think of this kind of slavery they think of the transatlantic slave trade. The closest thing we see to ethnic-based enslavement in the bible is when the Egyptians enslaved the Israelites. The Egyptians hated Hebrews (foreigners) long before Moses was even born according to Gen 43:32 and Gen 46:31-34, and they used their nationalism as justification for their mistreatment and enslavement of the Hebrews according to Exodus 1:8-10.