Some of the most successful therapies against cancer include those that target the T cells of our immune system. These so-called immunotherapies aim to boost our T cells so that they can kill the cancer. Not all T cells are the same. There is an unusual type of T cells, known as gamma delta (γδ) T cells, that are exceptionally good at killing cancers. We have been studying these γδ T cells for a long time and recently discovered that they have properties that can predict who will respond successfully to cancer immunotherapy. In this project we will use patient samples and a range of techniques to investigate how can these cells help us predict and improve the outcome of certain types of immunotherapy, and how does their biology change over the course of therapy. We hope to discover new ways to monitor patients under treatment and to be able to predict who of those will respond successfully. At the same time, we also hope to uncover more reasons to continue studying γδ T cells.