Finotonlimab is a reference monoclonal antibody targeting PD-1 (Programmed cell death protein 1, also known as PDCD1 or CD279). It serves as a standard in immunological research, bioassays, and quality control for developing and validating PD-1 inhibitors. By binding to the PD-1 receptor on T-cells, it blocks the interaction with PD-L1/PD-L2, thereby preventing immune evasion by tumor cells and restoring T-cell function. This reference antibody is commonly used in in vitro studies, flow cytometry, ELISA, neutralization assays, and pharmacokinetic/pharmacodynamic evaluations to mimic the mechanism of therapeutic anti-PD-1 antibodies applied in cancer immunotherapy for melanoma, non-small cell lung cancer, and other solid tumors. It is also utilized in research on hematologic malignancies and chronic viral infections. Not intended for direct clinical use; suitable for laboratory applications in biotech and pharmaceutical development.