The amount on Line 5 of your IT-196, State and Local income taxes, in addition to several other adjustments, get transferred down to Line 41 of IT-196.
If your income on Line 19 of your IT-201/203 is less than or equal to $320,000 if Married Filing Jointly, these adjustments get subtracted from your Itemized Deductions because they are allowed as a deduction under the IRC but not under New York Tax Law.
https://tax.ny.gov/pdf/current_forms/it/it196i.pdf page 20