eIF4E-IN-1 (WO2021003194A1, compound Y), is a highly effective inhibitor of eIF4E, a key protein involved in immunosuppression. By targeting immune checkpoint proteins such as PD-1, PD-L1, LAG3, TIM3, and IDO, eIF4E-IN-1 functions to disrupt immune suppression and promote immune release in specific diseases such as cancer and infectious diseases.