The article describes a rare case of Pneumocystis jirovecii infection complicated by left-sided hydropneumothorax in a patient with stage IVB clear cell renal carcinoma after immunotherapy. The patient had metastases to the descending colon, liver and upper pole of the left kidney with clinical stage T4NxM1. After administration of combined immunotherapy with PD-1 inhibitors (toripalimab) and antiangiogenic agents (sunitinib, axitinib), progressive dyspnea, chest tightness, hypoxemia, and anuria developed. The diagnosis was confirmed by chest X-ray, bronchoalveolar lavage and metagenomic sequencing of pathogenic microorganisms. Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection affecting immunocompromised patients, especially those with HIV and low CD4+ lymphocytes, with high mortality. PJP with hydropneumothorax after immunotherapy in cancer patients is extremely rare. The authors emphasize the need for early diagnosis and management of cancer patients undergoing immunotherapy.