This book is an accessible and in-depth popular science work on cancer immunotherapy. Starting with the intricate relationship between cancer cells and the immune system, it guides readers through the scientific principles and evolutionary journey of immunotherapy. From Nobel Prize-winning breakthroughs to modern applications of immune checkpoint inhibitors and cell therapies, and onward to cutting-edge advancements like cancer vaccines and oncolytic viruses, the book comprehensively illustrates how immunotherapy is reshaping the landscape of cancer treatment. It also unveils the profound connections between chemotherapy, radiation therapy, targeted drugs, and the immune system, while offering practical advice on boosting immunity through diet, exercise, and emotional management. Whether you are a cancer patient, a family member, or a curious reader fascinated by immunology, this book will inspire hope and illuminate how immunotherapy is ushering in a new dawn for humanity's battle against cancer.