Black Friday is an annual retail event. I don’t recall Apple not doing something on that day.
If the question is when, it is the Friday immediately after Thanksgiving in late NOV… so the 29th this year.
Yes I 100% expect Apple to participate in Black Friday that day. But again, you can prob get a better deal on Apple stuff from OTHER Apple retailers… today... or at about any time. Best Buy, B&H, Adorama, Amazon, etc often offers Apple's tech at better prices than Apple. I would not have big expectations of Black Friday moving Apple to offer better prices than some of those very stores... and similar.