Housing, job availability and potential erasure of culture. I think it depends on what migrants you let in though. Also some groups forming bubbles and refusing to integrate as well.
Personally though, I think kids watching american media on their mum’s ipads is a greater risk to our culture than Mohammed and his family down the street
Also, some immigrants are more racist than white people. Which is sometimes kind of funny. Although my white friend got beat up in Bradford, so sometimes it isn’t.