We explored the immune cell infiltration landscape of cancer samples with the highest ADAR expression (TCGA-FD-A3SR-01, TCGA−FD−A3SR−01, TCGA−GC−A3RB−01) and the lowest ADAR expression (TCGA-CF-A3MI-01, TCGA−CF−A47T−01, and TCGA−ZF−A9R4−01) in TCGA-BLCA using the Timer 2.0 database. The gene discussed is ADAR; the disease is bladder transitional cell carcinoma.