Might not have any tax liability left. We don’t know, because OP has not provided the information that would allow anyone here to determine that. And claiming a dependent will still be helpful to the millions of taxpayers who do have a tax liability that the $500 credit will apply against.
Up to $1,400 of the child credit is refundable. And the earned income credit is refundable as well.
The $500 dependent credit is not refundable I believe.
https://www.irs.gov/newsroom/whats-new-with-the-child-tax-credit-after-tax-reform