For example, we succeeded in generating a programmed death 1 (PD1, a glycoprotein) mutant via directed evolution with CHO cell display, which is much more stable and has an affinity for PD-1 ligand (PD-L1) of over 100-fold higher than the wild-type PD1 (our unpublished data), and the mutant PD1-Fc has an opportunity to be developed into a cancer drug due to its advantages regarding high affinity to PD-L1. Here, CD274 is linked to cancer.