If this question comes up, use it to make it clear how well you can work with your superiors. It also raises two important characteristics: loyalty and honesty. Make sure your answer explores these aspects of your working relationship with your current boss. Even if the relationship is strained, focus on any results you may have achieved together and your role in these results.
For example: 'My boss would tell you that I am good at coming up with solutions that are a little out of the box and which often give us the edge over our competitors. I'm also a good implementer so that when she has decided on a way forward, she can trust me to implement it well.'
With this question, the interviewer is looking for a cultural fit. If your potential boss is your interviewer, he/she will be looking for answers that show you are easy to work with and a contributor.
Be honest but never sound negative about previous bosses, as you will come across as a person who may be difficult to work with. Emphasise ways in which you interact with your current boss in your working environment to achieve the goals of the business and how this will help you in the new role you are applying for.