ALK and neoplasm: ALK (anaplastic lymphoma kinase)-positive tumors comprise approximately 5% of metastatic NSCLC, mainly adenocarcinomas of younger, non-smoker patients [4, 5], and are unique in many aspects: They typically have a lower number of genetic alterations compared to other NSCLC subtypes, as partly reflected by a mean tumor mutational burden (TMB) uniquely below 3 mut/Mb [6, 7].