immigrant - a person who comes to live permanently in a foreign country
expatriate - a person who lives outside their native country
the difference is that an immigrant is almost always permanent while an expatriate is often only temporary (ie. for school or for work). Also "immigrant" usually refers to someone who has become a citizen of the country they have moved to while "expatriate" is usually someone who lives in another country but doesn't become a citizen of that country
I guess white people are typically referred to as expatriates rather than immigrants because they are less likely to move out of their home countries permanently, since countries like Canada, US, etc. are not war-torn, are not impoverished, and do not have widespread human rights abuses, in contrast to many of the countries that POC "immigrants" are leaving (usually permanently). I wouldn't call it racist
Expats are shipped to another country by a company or corporation. Once the project is done, the company ship them to somewhere else. Usually employers have to pay a lot (on top of the normal wage) + free house + free cleaning lady + car with chauffeur in higher tiers + other conveniences for the inconvenience or risks of working abroad.
Immigrants are people moving to another country looking for jobs, a better life,... Bottom tier.
We have a different meaning of expat here. Like some posters mentioned above, it's someone sent (or "imported") from abroad because of their skills /education /experience. It doesn't have to be a white European, we have Chinese and Japanese companies here for example.
The lies I'm a Pole and my people are called immigrants in the western countries Unless you suggest that Slavs aren't white Those SJWs tears, trying so hard to find a reason to cry
I'm a Pole and my people are called immigrants in the western countries 
Those SJWs tears, trying so hard to find a reason to cry 