Lessons from neoadjuvant immunotherapy in melanoma: understanding antitumour immunity and tumour escape

Immunotherapy has become a fourth pillar of cancer therapy, alongside surgery, radiotherapy and chemotherapy. Cancer immunotherapy seems to be most effective in the context of low but not negligible tumour burden, thus in the neoadjuvant setting before curative intent surgery. Indeed, in the case of macroscopic stage III melanoma, a decade of clinical and translational research has led to conclusive evidence that neoadjuvant immunotherapy should be the clinical standard of care, although its adoption in different regions of the world is still ongoing. In this Perspective, we discuss the lessons learnt from neoadjuvant immunotherapy trials in melanoma and where the field is heading next. In the coming years, we believe that biomarker-driven personalization of the therapy, a deeper understanding of the role of immune education, and the ability to uncouple toxicity from efficacy will make neoadjuvant cancer immunotherapy safer and more effective, not only for melanoma but also for other types of cancer.