Illegal immigration does drive down wages for the unskilled.
https://www.usccr.gov/files/pubs/docs/IllegImmig_10-14-10_430pm.pdf
Then when Trump makes this claim, the left denies it.
https://www.washingtonpost.com/politics/2019/01/09/trumps-claim-that-black-americans-are-hurt-most-by-illegal-immigration-gets-pushback/