The most pronounced finding was that LCNEC could be categorized into two mutually exclusive groups based on the mutational patterns: type I LCNEC with key genetic alterations of NSCLC (STK11/KEAP1/KRAS) and type II LCNEC with the specific TP53 and RB1 co‐mutations of SCLC. Here, RB1 is linked to large cell neuroendocrine carcinoma.