Abstract
This review discusses the role of chronic human cytomegalovirus (HCMV) infection in patients receiving immune checkpoint blockade (ICB) treatment against different malignancies, with an especial focus on malignant melanoma. We briefly outline the impact of HCMV infection on the immune system as an entity before exploring its role in the context of cancer. We then address the potential impact on the efficacy of immunotherapeutic agents, particularly ICB, before looking at development of ICB-related autoimmune toxicity. Finally, we discuss potential avenues for future research.This article is part of the discussion meeting issue 'The indirect effects of cytomegalovirus infection: mechanisms and consequences'.