iPhone has long been Apple's branded product and main money, but sales are beginning to decline. The company is pushing digital subscriptions as it searches for new growth.
Apple is one of many American companies that are now embracing growing Chinese consumer fear. China is a major market for Apple and other smartphone manufacturers, accounting for one-third of the industry's global handset shipments.
In other comments, Cook said the world had "greater challenges than ever before."
"Climate change threatens our planet, poverty and inequality keep citizens and nations back from their potential, basic health care is still out for millions," he says.
"At the same time, we can have a healthy planet and a thriving economy. We can continue to lift millions of people out of poverty, and we can give everyone a chance to learn and prosper. To meet this potential, we all need to work together, government, academic institutions and businesses like Apple, "Cook said.