Since successful vaccination requires an immune system capable of mounting an effective response to the vaccine, DCprime continues to invest in research into furthering understanding of the condition of the immune system during or after treatment of cancer. T cells, the white blood cells that provide cellular immunity against viruses and tumours, play a dominant role in immune control of cancer. This notion, combined with the development of T cell based cancer therapies such as checkpoint inhibitors and adoptive T cell transfers, has dramatically shaped the new era of immunotherapy. At the same time, many different factors influence the successful eradication of tumours by T cells. Solid tumours, in particular, are capable of evading the immune system, for example by creating an inhibitory environment inside the tumour or by deterring T cells from entering the tumour completely. Also, the interaction of T cells with other constituents of the immune system leads to stronger or weaker responses against the tumour, or even to immune suppression. Thus, the key to effective immuno-oncology is to better understand the active status of combined immune responses composed of different immune cells, including dendritic cells, monocytes, macrophages and different T cell subtypes.