As a result between the people from the European continent and the people from the North American and South American continents, most of the native populations had died out.
Even though there's the general opinion that the main cause for this were the battles and the killing in them, even though they were numerous and there were casualties, the reason for the mass dying out was totally different, diseases.
The Europeans brought new diseases with them, and the Native Americans were not immune to them, so they spread around them very quickly and they were dying very quickly, which lead to a depopulation of large ares of the continents.