Pathological response and tumour bed histopathological features correlate with survival following neoadjuvant immunotherapy in stage III melanoma

•Eighty-three lymph node dissections following neoadjuvant immunotherapy for stage III metastatic melanoma were assessed.•There was strong reproducibility in assessment of INMC pathological response category and percentage of viable melanoma.•High fibrosis was associated with a lack of recurrence and increased RFS, representing a possible biomarker.•Two different scoring systems of response were assessed and both scoring systems correlated with a lack of recurrence.•High fibrosis was also associated with increased levels of B cells within the tumour bed.