In this work, we found that MED12 mutation was significantly associated with prolonged survival in ICI-treated NSCLC patients (MSKCC/Naiyer/our own cohorts), but not non-ICI-treated patients (TCGA cohort), indicating that it is a specific biomarker for ICI treatment of NSCLC, but not standard of care or other treatment type. Here, MED12 is linked to non-small cell lung carcinoma.