There is a BIG difference between immigration and slavery. In slavery you are a servant a slave of someone and have to do WHATEVER they want u to and in immigration you migrate to another country of which you aren't a native citizen in order to settle there.There's a HUGE difference between the two!
Immigration is someone who immigrate to live in other country, and slavery is someone who work hard for someone, he/she is like the maid, even he/she was bought from his/her country to work for all of their life.