Marvel decided they need a big boost to Doctor Strange before his second film comes out and decided a 'death of' story is a perfect opportunity for new readers.
The 5-issue "Death of Doctor Strange" with the team of Jed MacKay and Lee Garbett begins in September and has the following synopsis:
Strange was the only hero standing in the way of powerful new villains eager to claim Earth as their own. When he unexpectedly dies, who is left to protect Earth and keep the mystical evils at bay? And most importantly…who killed Stephen Strange? If he couldn’t stop them, who can? This rousing journey will dive into the mythos behind Doctor Strange, showcasing his unique—and vital—position amongst Marvel’s heroes and ultimately transform the future.