Slightly different (or vastly, depending on your work) than leaders, managers are something that everybody has something to say about. Love them or hate them, they’re an essential subject to discuss in business. Perhaps some of your students are managers themselves. You could ask:

What do you think about your manager(s)?

What qualities make a good manager?

How does your manager spend their time?

How can a manager motivate employees?

What is your manager’s managing style?