Blacks were always in the americas and were the aboriginal Americans encountered by Columbus.

In his writings, Columbus described them as the copper-coloured blue-black Indians.

Olmec heads are clearly black. There is no record of the thousands of ships that would have been required to ship such a large population of slaves that would be necessary to explain the black population that exists in the American continents today. No catalog of existing ships, no findings of ships that went under. Also, how could these ships carry enough food and water for the amount of slaves they supposedly carried?

Mayan and Aztec codices/murals clearly show them as being black people.

The oldest skeletons found in the Americas, thousands of years old, are clearly black based on their morphology. Look at luzia woman and the Lagoa Santa people.

Pic related are the angeles mesa skeletons found in California dating back thousands of years. Clearly the skull of a black man. Note the wide set eyes, rectangular orbits, strong brow ridge, prognathism of the jaw and the wide, rounded nasal cavity.

The Asian Eskimos came from Siberia way after and are not the real Indians.