In thymoma, the most common alterations were TP53, DNMT3A, and CDKN2A, with frequencies of 7.8%, 6.8%, and 5.8%, respectively; TMB higher than 10 mutations/Mb was present in 1.6% and MSI in 0.3% [57]. The gene discussed is CDKN2A; the disease is thymoma.