The announcement of the 9th edition of TNM staging system for thymic tumors was one of the highlights at the World Conference on Lung Cancer 2023. The revision, based on a larger and more detailed database, provides changes and confirmation from the last system. The 9th edition of TNM staging system aims to balance statistical significance and clinical feasibility. The birth of an improved TNM staging system heralds the changes that will follow in clinical practice and scientific research.