Marking a topic with "de hua"
You probably already know that 的话 (de huà) can be put at the end of a phrase to express the meaning of "if." It can be used independently, or with 如果, both meaning "if". But it can also be used to simply identify a topic, sort of like saying "when it comes to...."
的话 can also be used to introduce a topic which the speaker intends to say more about.
[topic] + 的话...
- 云南 的话，春天 去 最好。With Yunnan, spring is the best time to go.
- 晚上 的话，当然 方便 啦。The evening? Of course that's convenient.
- 我 肯定 能 去 。 他的话，我 就 不知道 了。I can definitely go. As for him though, I don't know.
Sources & further reading
- Chinesegrammar.info: Chinese grammar de hua (的话): expressing “if” in Chinese with de hua