A person forced to leave his or her country is

an emigrant.

an immigrant.

an exile.

a fugitive.

A person forced to leave his or her country is an exile. If this person is forced to leave his own country, it means that they are exiled for a certain period of time (or forever), during which they have to move to another country. They cannot be called immigrants or emigrants, given that they aren't willingly moving. A fugitive is usually a person who is running away from a war or law in their own country.