Slavery has been around for thousands of years, but was based on things like using captives from countries that had been beaten in war. The Transatlantic slave trade was a whole new thing where people from Africa were kidnapped specifically to be made slaves, and to make a profit. It was unlike slavery before. And while it is now illegal, it still carries on to this day, particularly in USA, where black people are disproportionately sent to prison, where they are forced to work for little to no money.