Three hundred and fifty NSCLC pts with next-generation sequencing (NGS) and immunotherapy data obtained from MSK-IMPACT clinical cohort (MSKCC) were used to explore the association with ARID1A and/or ARID1B mutation, TMB and efficacy of ICIs....The survival probability of mutation group was significantly longer than wild-type group (P=0.038)....The results indicated that ARID1A and ARID1B mutations were associated with a higher TMB level in both MSKCC and Chinese NSCLC patients, and patients with these gene mutations may benefit more from ICIs.