The immune system can fight cancer by eliminating malignant cells or by preventing the outgrowth and spread of cancer cells that resist immune eradication. Importantly, the latter mode of control, termed ‘cancer-immune equilibrium’, can be maintained for long periods of time, possibly several decades. Therefore, a better understanding of the nature and spatiotemporal dynamics of immune responses affording this type of durable protection will be of great value for the development and improvement of future cancer immunotherapies. We have developed a transplantable melanoma model that approximates distinct disease stages seen in patients, including progressively growing tumours with metastatic spread, stably controlled tumours and long-term persistence of occult melanoma cells in absence of tumours. The latter two outcomes reflect a ‘melanoma-immune equilibrium’. We have built a number of key technologies around this model, including in vivo and ex vivo imaging techniques, as well as a gene editing platform that we are using to generate melanoma variants tailored to address defined experimental questions. Applied to our novel model, these tools uniquely permit tracking, manipulation and imaging of melanoma and tumour-specific T cells, including a direct visualisation of localizsed T-cell-mediated tumour suppression. We are currently using this set-up to elucidate the contribution of resident memory T cells and other immune cells to the stable control of cutaneous melanoma and to uncover basic molecular pathways involved in efficient tumour suppression. Such fundamental knowledge that has the potential to guide the development and improvement of future cancer immunotherapies.