Abstract: A PD-1 variant, which has improved binding affinity to PD-L1, and methods for preparing and screening the PD-1 variant. The PD-1 variant of the present disclosure effectively inhibits the binding between wild-type PD-1 and PD-L1, and thus is expected to have significantly higher penetration ability and anticancer effect by immune cells or therapeutic effect for infectious diseases as compared to existing immune checkpoint inhibitors. At the same time, the possibility of immunogenicity can be minimized. In addition, the convenience of developing biomedicine may be promoted through aglycosylation.