Envafolimab (ASC 22; KN 035), a recombinant humanized single-domain anti-PD-L1 antibody, integrates the anti-PD-L1 domain with the Fc fragment of the human IgG1 antibody. It inhibits the PD-L1 and PD-1 interaction with an IC 50 of 5.25 nM, indicating its research potential for solid tumors [1] [2] [3].