The Islamic State in West Africa (ISWA) has announced that it has replaced Abubakar Shekau with Abu Musab al-Barnawi. Abu Musab "takes over all territories that were under Shekau. The immediate replacement of Shekau was a major revenge against the former Boko Haram leader that exhibited ‘highhandedness and ruthlessness’ against humanity in the Northeast." The announcement also included that ISWA had arrested thirty top commanders that were loyal to Shekau.
It appears that ISWA has absorbed Shekau's faction. A credible hypothesis is that the thirty commanders "arrested" will either switch allegiance to Abu Musab or be killed, with the former alternative the more likely. ISWA is already the larger fighting force: in February 2019 it was estimated to boast around two to three times more fighters (3,500-5,000) than Shekau’s faction (1,500-2,000).
It should be noted that there is still no definitive evidence that Shekau is dead. The Nigerian government has been careful to say that it is still investigating; no corpse, or even a picture of a corpse that might serve as proof of death, has been found. That said, there has been no statement by Shekau's supporters that he is still alive.
It remains to be seen whether this apparent consolidation of Boko Haram factions will make the movement more lethal and dangerous to the Nigerian state. Shekau's displacement or demise raises the question of what group now hold the more than one hundred Chibok schoolgirls that remain in captivity. It is to be hoped that there might be some movement toward their release.