The most frequent mutation occurred in TP53 and RB1, consisting with prior reports.34 Previous studies indicated that TMB seemed to correlate with clinical activity in patients treated with single agent immunotherapy (nivolumab monotherapy) or PD-1 plus CTLA-4 blockage (nivolumab plus ipilimuma), but not for chemo-immunotherapy combinations in ES-SCLC.6,35,36 In the current study, patients with high TMB had better survival outcomes. Here, CTLA4 is linked to small cell lung carcinoma.