Migration and immigration are related terms, but they have slightly different meanings.
Migration refers to the general movement of people from one place to another. This can include people moving within a country (such as from one state or province to another) or between countries. Migration can be voluntary, such as when people move to a new city to find better job opportunities, or involuntary, such as when people are forced to flee their homes due to war or persecution.
Immigration specifically refers to the movement of people across national borders in order to take up permanent residence in a new country. Immigrants are individuals who move to a new country with the intention of living there permanently, and in many cases, becoming a citizen. They are usually subject to legal requirements and regulations that differ from those for short-term visitors.
In short, all immigration is migration, but not all migration is immigration. It’s a specific type of migration that occurs across national borders and with the intention of taking up permanent residence in a new country.