From what I understand, the ancient world had some generalized xenophobia towards people outside their own language/culture, but it wasn’t focused on white/black and hierarchies based on skin color like what came with European colonialism.

Related, I found this on Wikipedia which I think is an accurate summary:

The term "Aethiop" carried no social implications.[4] There was no such thing as a black community; immigrants from south of the Sahara were few and from disparate ethnic communities. The immigrants would have been separated from each other in households of other people, and if they had descendants these would have blended within very few generations into the local population.[4] While slaves formed a large minority of the population and slavery was a deeply stigmatized social status, the great majority of slaves were from European and Mediterranean populations; inherited physical characteristics were not relevant to slave status.[4][5] Black people were not excluded from any profession, and no stigma or bias against mixed race relationships is recorded in Antiquity.[6]

So, yeah, racism as we know it today didn’t really exist back then.