Key Clinical MessageAlthough immunodeficient patients are less prone to develop Coronavirus disease 2019 (COVID‐19)‐mediated cytokine storm, secondary infections can cause serious complications in this vulnerable population. They are more likely to develop opportunistic infections that can mimic the symptoms of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection. Herein, we presented a 27‐year‐old male patient of SARS‐CoV‐2 infection, who was complicated withPneumocystis jiroveciipneumonia (PJP), following treatment with rituximab. First, he was hospitalized for 5 days with fever, cough, and dyspnea due to COVID‐19 infection, and treated with remdesivir and glucocorticoid. Then, he has been referred to our center with cough, dyspnea, body pain, and fever. Due to persistent fever, the progression of pulmonary lesions, and reduced oxygen saturation, we began treatment with piperacillin + tazobactam, vancomycin, and levofloxacin. Nevertheless, the patient's fever did not stop after the aforementioned empiric treatment and his condition got worse and he was admitted to the intensive care unit. The result of BAL fluid, tested forP. jiroveciiby RT‐PCR, turned out to be positive. Therefore, we started trimethoprim‐sulfamethoxazole and dexamethasone, which improved his condition. We hope this article helps clinicians consider causes other than COVID‐19, especially opportunistic infections such as PJP, in patients with respiratory symptoms and fever.