When the time comes, it’ll signify the end of an era. Cook will step down, leaving behind an indelible mark on Apple, which has become the most valuable company in the world, surpassing a $3 trillion market capitalization under his leadership.

His successor will inherit a transformed technology giant, facing numerous challenges in a much-changed landscape at the same time. The successor will need to maintain the delicate balance between innovation and stability that defines Apple’s success.