Since they tend to be near 100% for dems, the only way they would be significant is if the vote for Trump.
Which tells me this "journalist" is full of crap. Black females are the most monolithic block for dems that exists. There will be no shift, and they will turn out and vote the same as they have for the past 3 elections. Black males may shift to Trump in a small way, maybe 5% more than 2016, but not a significant move. The group with potential to shift right are legal Latino immigrants. The group likely to add votes to the left are illegal Latino immigrants, and today SCOTUS gave them the sign to go ahead and vote. But as always, it's all about getting YOUR side to the polls by exciting and motivating them.