This means Sabih Khan is running operations now. Jeff Williams’s title hasn’t changed, but he’s effectively now running product development. He’s led the Apple Watch product team from its inception; now I think he’s overseeing product for everything. Cook and Williams did run operations while holding the COO title, but what “COO” really means at Apple is “second in command”. Tim Cook didn’t move design under operations; he promoted Williams to a new position, effectively “chief product officer”, and as such it makes sense that Hankey and Dye would report to him.
Source: Daring Fireball: On the Post-Ive Future of Design at Apple