The International Collaboration on Cancer Reporting (ICCR) would like to thank Dr Ian Cree for his work as Head of World Health Organization (WHO) Classification of Tumours at the WHO International Agency for Research on Cancer (IARC) since 2017. Dr Cree is retiring from this role on 7 July having successfully transformed the structure and content of the WHO Classification. The 5th edition of the WHO Classification of Tumours provides a globally accepted common framework for the diagnosis and treatment of cancer, as well as a key resource for cancer research and education. The ICCR is very grateful for the close coordination between the WHO ‘Blue Books’ and the ICCR dataset projects, including the hyperlinks from the on-line Classification to appropriate ICCR datasets. The support from Dr Cree and his team for the work of the ICCR has been invaluable.