The hardships and ups and downs in life. According to the query on Kugou Music Network:

1. "Cloud River" is a song sung by singer Huang Yingying and written and composed by Liu Jiachang. The lyrics express the hardships and ups and downs in life.

2. Excerpts from the lyrics: River of clouds, river of clouds, there is me in the river of clouds, drifting by the wind and never finding the real me.