Migration effects three main categories culture, economy, and politics.
Culturally when different groups are in one area they teach each other. They learn new foods, clothes, and beliefs adding diversity to a group.it may though also cause other groups to discriminate each other.
Economically if the groups fills jobs, or bring new talents they can help the economy. On the other hand a new group can strain a regions resources. By doing this water and security can lower.
Politically a new group can change policies and government. These new people can be viewed unwanted and dangerous and governments can back these causes. In other times a new group will bring valuable skills and have a chance to become citizens.