CCTV public service advertisements are often interspersed with some famous songs or original music, which can usually touch people's emotions and convey the information to be expressed in the advertisements.
For example, in the Spring Festival Evening of 20 17, after the sketch "My Wife" performed by Cai Ming and Pan Changjiang, a public service advertisement "Love to Be Together" was broadcast, in which the episode was "If the Cloud Know", which is a classic old song of Wan Fang.
In addition, some public service advertisements use famous classical music as the soundtrack, such as Home (Spring Festival Overture), Baby in a Dream (Jasmine and Fishing Boat Sing Late) and so on.
If you can provide more details, such as the release time of the advertisement and the specific scenes used in the series, etc. Maybe I can give you a more accurate answer.