The present invention discloses a benzyl phenyl ether derivative, a preparation method therefor, and a pharmaceutical composition and uses thereof. Specifically, the invention relates to benzyl phenyl ether derivatives represented by formula (I), a pharmaceutically-acceptable salt thereof, a stereoisomer thereof, a preparation method therefor, a pharmaceutical composition containing the one or more compounds, and uses of the compounds in treating diseases related to PD-1/PD-L1 signal channels, such as cancers, infectious diseases and autoimmune diseases.