Immune-related adverse events following treatment with immune checkpoint inhibitors can affect almost every organ. Tislelizumab, a novel humanized Ig G4 programmed death receptor 1 inhibitor, was started for bladder cancer in 2019, but the adverse effects of this drug may not yet be known due to its short time on the market, and there are still some clinical safety concerns. There are few reports of adrenal insufficiency after tislelizumab treatment, which is easily missed, misdiagnosed and life-threatening.A 67-year-old male with bladder cancer who developed rash, water-sodium retention, electrolyte disturbances, hypoalbuminemia, low-grade fever, nausea and vomiting, and fatigue after 2 cycles of tislelizumab.Immune checkpoint inhibitor-related adrenal hypofunction and Psoriasisby.Suspended tislelizumab treatment and continued glucocorticoid therapy.The patient showed significant improvement in the above symptoms. But bladder cancer reemerged at the same site.The advent of immune-related adverse events has increased the complexity of the application of tislelizumab in the treatment of bladder cancer and further research is needed to develop the best treatment guidelines. Early diagnosis and treatment are crucial since the adverse events could endanger lives.Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.