This chapter presents an overview of cancer prognosis and current treatments such as surgery, radiotherapy, and chemotherapy. It begins by looking at cancer prevention. Predicting the expected outcome for patients diagnosed with cancer is a critical step in their management; however, prognostication has remained somewhat subjective, leading to suboptimal clinical outcomes. The chapter then considers immunotherapy, which aims to treat cancer by generating or enhancing an immune response against the tumour. Immunotherapy differs from other methods of cancer treatment in that it does not target the tumour cell directly but instead targets the immune system. Principally, three strategies are utilized: immune checkpoint blockade, adoptive T cell transfer, and cancer vaccines. The chapter also describes how clinical trials of new candidate drugs are currently undertaken.