Around 2011, the field of oncology underwent a profound transformation with the widespread emergence of immunotherapy. This innovative approach to cancer treatment represents a fundamental shift in medical strategy, moving away from traditional methods that target tumours directly and instead harnessing the body's own immune system to identify and eliminate malignant cells. By empowering the immune response to recognise cancer as a threat, clinicians have been able to achieve durable remissions in patients who previously had few viable options.

The clinical success of this approach is largely attributed to the development of sophisticated therapies that overcome the mechanisms cancer cells use to evade detection. Key advancements in this area include:

• The introduction of checkpoint inhibitors, which release the brakes on the immune system to allow for a more robust attack on tumours.
• The development of engineered cell therapies, such as CAR T-cell therapy, which involve modifying a patient's own immune cells in a laboratory setting.
• Improved long-term survival rates for specific types of cancer that were historically considered difficult to treat.
• The establishment of new protocols for managing the unique side effects associated with immune-mediated responses.

Despite these significant breakthroughs, the integration of immunotherapy into standard clinical practice has introduced a complex array of new challenges. The nature of these treatments often brings about distinct clinical risks, including autoimmune-like side effects that require careful monitoring and specialised management. Furthermore, the high cost of developing and administering these advanced therapies has prompted ongoing discussions regarding healthcare economics and equitable access for patients globally.

As the medical community continues to refine these techniques, the focus has shifted towards understanding why certain patients respond exceptionally well to treatment while others do not. This has led to an increased emphasis on biomarker research and combination therapies, aiming to broaden the efficacy of immunotherapy across a wider spectrum of cancer types. The legacy of this period is defined by a permanent change in the therapeutic landscape, marking a new era where the immune system is viewed as a primary weapon in the fight against cancer.