Zhu et al. showed that ARID1A and TTN genes were among the 11 genes with frequent mutations in bladder cancer (Zhu et al., 2020), indicating their importance in predicting immune response in bladder cancer, and suggesting that co-mutations of ARID1A or TTN with ATM may be potential molecular biomarkers for predicting the efficacy of immunotherapy for bladder cancer. The gene discussed is ARID1A; the disease is urinary bladder cancer.