Last fall, Daredevil was the latter and so T'Challa became the former; this fall, Matt's the first again and so the Panther's assuming the second legend.
This second transition's marked like the first, by an event and with a tonal shift. It's a lighter one this time, with Daredevil having gone from Maleev to Martin and T'Challa's Most Dangerous Man Alive Francavilla covers looking.. well, like Hell's Kitchen in the evening rather than Zircher and Bianchi's Hell's Kitchen at night in Man Without Fear (that is to say, softer colors).
The stories're likewise flipping the switch: we've already begun to see Daredevil taking up a discarded mindset for his superheroic penance, and now it's the Panther's turn. The change's marked by the events of Fear Itself, and T'Challa's own agent of is a much more personal one- a new Hate-Monger, possessed by and possessing the original's hate powers.
( The one more touted, the controversial American Panther promised to have a 'huge impact'.. he's a subordinate, according to last month's #521. )