By Fisher's exact test, we found a significant association between TMB‐H and multiple gene mutations, including FAT1, TP53, SPTA1, KEAP1, KMT2D, MAGI2, NOTCH2, NOTCH3, FLT1, KDM6A, and FAT4, in the Chinese SCLC patients (Table S3). Here, FAT4 is linked to small cell lung carcinoma.