In the evolving landscape of cancer treatment, two warriors stand out on the battlefield of medical oncology—chemotherapy and immunotherapy. Both have their unique strategies in combating cancer, yet they represent fundamentally different approaches. Prior to contemplating any one of these two alternatives, a confirmed diagnosis must be made using a variety of diagnostic techniques, including tissue biopsies, imaging tests like PET-SCAN, blood tests with certain specific markers, medical examination, and symptoms assessed by a specialist or healthcare provider.