If required, your son files his own tax return weather you claim him or not.
If your son is a college student, his earnings may not matter. He could still qualify as your dependent.
Under no circumstances will you include your son's income, on your tax return. Again, it doesn't matter if you claim him as a dependent or not - assuming you qualify to do so.
For your son:
If he has more than $12K of ***EARNED*** income reported to him on a W-2, then he is required to file a tax return.
If your son has more than $400 of self-employment income, then he is required to file a tax return.
If your son as more than $1100 of investment income (such as dividend or interest income) then he is required to file a tax return.
Again, your son's requirement file or not, has no impact on you qualifying to claim him as a dependent, assuming he was a college student in 2020.
