The Tax Cuts and Jobs Act:
Denies the Child Tax Credit (both refundable and non-refundable portions) to immigrant children
without a Social Security Number (SSN). As with many of the individual tax provisions, this
change expires on December 31, 2025
For these purposes, a SSN must be issued before the due date for the filing of the return for the
taxable year.
However, children who would otherwise qualify for the CTC, except that they lack a SSN, ARE
eligible for the new non-refundable $500 family tax credit.
https://www.nilc.org/wp-content/uploads/2018/02/ITIN-field-call-2.8.18.pdf
