If people move to the city they work in, they would not only be workers but also citizens. Thus increasing the supply of workers. But also the amount of consumers. It's a two way street. Importing work force that only work during the day and then leave is however bad I would say. People that are sick are also a toll (that's expected to yield return someday, future investment).

That is just my uneducated take on it.

When I search for the terms immigration wages I get the following sources:

https://www.sns.se/en/archive/effects-of-immigration-on-nati... https://fullfact.org/immigration/immigration-wages/