Background: CC chemokine receptor 4 (CCR4) is the receptor for CCL22 and CCL17, which is expressed on the surface of tumor cells from patients with adult T-cell leukemia/lymphoma (ATL), peripheral T-cell lymphoma (PTCL) and cutaneous T-cell lymphoma (CTCL). Mogamulizumab is a humanized, IgG1 kappa monoclonal antibody that is directed against CCR4. By reducing the number of CCR4 positive Treg cells, the mogamulizumab can boost antitumor immunity and achieve anti-tumor effects.Methods: We examined the PubMed and ClinicalTrials.gov without any language restrictions until 1 February 2020. Considering variability in different studies, the overall survival (OS), progression‐free survival (PFS), objective responses rate (ORR) and Hazard Ratio (HR) were selected to evaluate the efficacy. Besides, adverse events (AEs) were calculated to assess the safety.Results: When patients were treated with mogamulizumab monotherapy, the most common all-grade AEs were lymphopenia, infusion reaction, fever, rash and chills while lymphopenia, neutropenia and rash were the top 3 grade ≥3 AEs. In combination therapies, the top 3 all-grade AEs were neutropenia, anaemia, and lymphopenia, and lymphopenia is the most common grade ≥3 AE. Besides, the overall ORR is 0.430 (95% CI: 0.393-0.469) and the pooled mean PFS is 1.060 months (95% CI: 1.043-1.077) in mogamulizumab monotherapy. In combination therapies, the overall ORR is 0.203 (95% CI: 0.022-0.746) while the overall PFS and OS were 2.093 months (95% CI: 1.602-2.584) and 6.591 months (95% CI: 6.014-7.167), respectively.Conclusions: On the basis of present evidence, we believed that mogamulizumab had clinically meaningful antitumor activity with acceptable toxicity which had a considerable potential in treating patients with cancers.