The movement of populations in modern times has continued under the form of both voluntary migration within one 's region , country , or beyond , and involuntary migration ( which includes slave trade , Trafficking in human beings and ethnic cleansing ) . The movement of populations in modern times has continued under the form of both voluntary migration within one 's region , country , or beyond , and involuntary migration ( which includes the slave trade , trafficking in human beings and ethnic cleansing ) .