More influential in racial diversity/demographic urban change (in recent past & now?)

[Capsicum]

Cities are generally more racially diverse than their hinterlands. This can be accounted for by a number of factors that involve among other things, either domestic minorities moving there, or international immigrants moving there.

Which factor do you think was and is more influential in the recent past and currently in driving racial demographic changes and the patterns of racial demographics seen among cities?

Domestic migrations and movements of racial minorities causing changes in their distribution across cities (such as the Great Migration to the northern and western cities of native-born Black Americans, and then the reverse Great Migration to the Sunbelt, tensions such as white flight and suburbanization, plus later suburbanization of minorities like the black middle class in Atlanta, other domestic migrations and movements of minorities like Puerto Ricans moving to the mainland, like NYC, Hispanic/Mexican-Americans moving around the US state to state as workers, even Japanese-American internment changing where they lived).

or

International immigration causing changes in the distribution of racial diversity, many immigrants who arrive and choose to live in cities (notably the reforms of racially-based immigration policy and post 1965 opening up the US to the world. The decline of immigration from Europe (that previously made up huge amounts of immigrants to the largest cities in the US, like NYC and Chicago, such as the Irish, Italians etc.) and the increase in immigration from Latin America, Asia, and Africa)