Studies show that humans are genetically linked to Africa.
The definition of “immigration” is to move to a different place permanently.
Since we originated from Africa, everyone that is not living in Africa is an immigrant / descended from immigrants.
Everyone is an immigrant, people migrated for many reasons, sometimes against their will. But ultimately we moved out of Africa, which is immigration.
https://pmc.ncbi.nlm.nih.gov/articles/PMC2945812/