Immune Checkpoint Inhibitors (ICIs) have dramatically revolutionized the therapeutic approaches by which we treat a series of cancers accompanied by immune-related adverse events (irAEs). Herein, we reported an intrahepatic cholangiocarcinoma male patient with a history of ankylosing spondylitis developing pulmonary arterial hypertension (PAH) under ICI combined therapy with pembrolizumab and lenvatinib. The indirect measurement of cardiac ultrasound showed a pulmonary artery pressure (PAP) of 72mmHg after 21 three-week cycles of ICI combined therapy. The patient partially responded to the treatment of glucocorticoid and mycophenolate mofetil. The PAP decreased to 55mmHg 3 months after the ICI combined therapy was discontinued, but increased to 90mmHg after the ICI combined therapy was rechallenged. We treated him with adalimumab-an antitumor necrosis factor -alpha (ani-TNF-alpha) antibody-combined with glucocorticoid and immunosuppressants under lenvatinib monotherapy. The patient responded again with PAP decreasing to 67mmHg after 2 two-week cycles of adalimumab. Accordingly, we diagnosed him to have irAE-related PAH. Our findings supported the use of glucocorticoid disease-modifying antirheumatic drugs (DMARDs) as a treatment option in refractory PAH.