Slavery was widespread throughout the ancient world. However, some of the most common examples seem to differ qualitatively from slavery as it's commonly conceived today. For instance, Greek slavery was often the result of war or more similar to later Medieval serfdom, whereas African and Middle Eastern slavery seems to have allowed the children of slaves to essentially become family members, albeit possibly of a lower social status. In many of these cases, slavery was not hereditary, and the children of enslaved people could become free.
Neither of these was quite the same as later chattel slavery in the Americas, where enslavement was hereditary with a growing enslaved population, and enslaved individuals could legally be bought and sold.
Obviously, the prevalence and importance of chattel slavery exploded with European colonization of the Americas, primarily through the enslavement of Africans. However, how common was chattel1 slavery worldwide before the trans-Atlantic slave trade?
1: While the term can be a little vague, by chattel slavery I mean slavery in which individuals are legally considered property to be disposed of as the putative owner wishes, and in which slavery is both heritable and frequently inherited. For instance: serfdom probably wouldn't count, because even though the lord controls the labor of their serfs, and serfdom is inherited, the lord couldn't do whatever they wanted with their serfs, or directly sell or buy them.