According to current European Medicines Agency (EMA)-approved guidelines for first line therapy of bladder cancer with pembrolizumab (CPS ≥ 10) and atezolizumab (IC-score ≥ 2/IC ≥ 5%), a single ARID1A-mutated cancer (1/3) was identified to be potentially eligible for atezolizumab first line therapy (Supplementary Table S5). The gene discussed is ARID1A; the disease is urinary bladder carcinoma.