PDCD1 and hepatitis B virus infection: However, little information is available when it comes to the efficacy, resistance, and underlying mechanisms of ICIs.<h4>Case presentation</h4>A 67-year-old woman was diagnosed with pulmonary sarcomatoid carcinoma (PSC) with a history of hepatocellular carcinoma (HCC) and viral hepatitis B. Following the lack of response to systemic chemotherapy, she was treated with camrelizumab, an anti-programmed cell death protein 1 monoclonal antibody, in combination with chemotherapy, and a partial response was obtained both in PSC and HCC.