Here's Times/Siena polling of 589 Black voters nationwide.

Some slippage from 2020 numbers (albeit we won't know till the election how accurate this polling is). But an improvement from Biden's earlier polling of this group.

The slippage is primarily among Black men.

A decent amount are still undecided, so Harris can improve.

Margin of error is relatively high at 5.6%. Which could really change the interpretation of this poll versus the actual result.

(Fwiw the poll includes multiracial and Hispanic black voters, Harris is doing slightly better among non-Huspanic and non-multiracial black voters in the poll)