A longtime Starbucks (SBUX) executive is retiring as CEO Brian Niccol tries to turn around the flagging coffee chain. On Monday, Starbucks North America CEO Michael Conway, 58, announced plans to retire.

Starbucks officially has a new CEO, with Brian Niccol taking over the top job Monday. Here are challenges he is facing that have hampered Starbucks' sales and stock price in recent months.

Starbucks CEO Brian Niccol had his first day on the job Monday — and yes, he was in the company's Seattle headquarters. Niccol, the California-based former head of Chipotle, joined the coffee giant following the ouster of former CEO Laxman Narasimhan last month and will be under the gun to turn around Starbucks' lackluster financial performance.

We caught up with three experts to weigh in on what leaderships lessons Brian Niccol can apply as he takes over as CEO of Starbucks.

Michael Conway will be retiring at the end of November, according to a Monday filing. His position won’t be filled.

Michael Conway, Starbucks’s North American chief executive, plans to retire Nov. 30 after only about eight months in the role. Conway informed the coffee chain of his decision on Thursday, according to a Monday filing with the Securities and Exchange Commission.

The new role will oversee product, marketing, digital, customer insights, creative and store concepts.