Schizophrenia is a complex chronic mental disease with unknown etiology. At present, the diagnosis is mainly based on the clinical manifestations of patients and the observation and evaluation of symptoms by doctors. There is a lack of objective biological indicators. The validity and reliability of its diagnosis still exist. In recent years, studies have found that immune inflammation plays a role in the pathogenesis of schizophrenia. After anti-inflammatory treatment, the symptoms of some patients with schizophrenia can be alleviated to a certain extent. The role of immune cells in diagnosing and treating mental diseases has gradually been paid more attention. This review focuses on the role and potential diagnostic significance of peripheral blood mononuclear cells (PBMCs) as carriers of biomarkers in the pathogenesis of schizophrenia, which is helpful to understand the immunophenotype of schizophrenia.