In Wakanda, Killmonger becomes the official Black Panther when Everett Ross, who is the stand-in for T’Challa as ruler of Wakanda, yields on T’Challa’s behalf (because T’Challa is being beaten to death by Killmonger).
By relinquishing the rights to the spiritual Black Panther role, even against his own will, T’Challa is now dying. So, Brother Voodoo goes to Moon Knight to see if the Moon God Konshu will intercede on T’Challa’s behalf.
Moon Knight is a scary partner.
This leads to a walk through some kind of astral plane.
Lots of weird fun stuff.
It eventually leads to the realm of Nightmare.
In the end, T’Challa is not dead.
In the epilogue, the “new” Black Panther (Killmonger) shows up at Avengers Mansion and Achebe solicits help from Deadpool–who will crossover with Black Panther, next.
It’s the same page that appeared in Deadpool #42.