The host country will receive more labor, both skilled and unskilled.
The emigrants will be able to send money back home.
Diversity will increase in host country
Competition for resources in the country being emigrated from is reduced.
Disadvantages
Workforce reduces in home country of emigrant.
Possible "Brain Drain" - Brain drain refers to when skilled people such as doctors leave a country and go to another. The country they left will suffer because there is now less skilled labor in the country.
Overcrowding in host country
Conflict might arise due to clash of cultures in host country