In lung cancer cells where ARID1B is knocked down, the activation of the cyclic GMP‐AMP synthase‐stimulator of interferon genes (cGAS‐STING) pathway is augmented, and this activation improves the efficacy of immunotherapy, the high expression of ARID1B is correlated with immune suppression, low immune scores, decreased immune cell infiltration, and negative correlations with various immune‐related cell types and functions. Here, ARID1B is linked to lung cancer.