Envafolimab (ASC 22; KN 035) is a recombinant protein of a humanized single-domain anti- PD-L1 antibody. Envafolimab is created by a fusion of the of anti-PD-L1 domain with Fc fragment of human IgG1 antibody. Envafolimab blocks interaction between PD-L1 and PD-1 with an IC50 value of 5.25?nM. Envafolimab has the potential for the research of solid tumors.