I want to invite my boss to dinner. What should I say during the dinner to adjust the atmosphere?

If you really have nothing to say, just talk about his recent performance that he is proud of. This will make him very happy, and maybe you can learn something.

If he is unwilling to say more, change the topic quickly. The boss must have a lot of social activities and is very knowledgeable about food. It is also a good idea to introduce more topics while eating and drinking.