However, the involvement of the PD‐1/PD‐L1 pathway in the immunosuppression of chronic infections in pigs has not yet been elucidated, because monoclonal antibody (mAb) against swine PD‐1 and PD‐L1, which could be powerful tools for elucidating the pathogenesis of swine diseases, have not yet been reported. This evidence concerns the gene CD274 and swine disease.