Human metapneumovirus (HMPV) causes a flu-like disease in humans. Most infections occur in early childhood, but reinfections during life are common. The clinical course of these infections are usually mild and do not require hospitalization. However, this is not the case for older and/or comorbid patients, especially if lymphoma is a concurrent disease. Here, we report on a case of an 81-year-old man, who suffered from chronic lymphocytic leukemia. During the first coronavirus disease (COVID) wave, he was admitted to the emergency department with respiratory symptoms. Initially, he was suspected as having SARS-CoV‑2 infection, but a broad diagnostic approach revealed a HMPV infection. The patient showed remarkable, bilateral pulmonary infiltrates and worsened within a few days. Consequently, he had to be admitted to the intensive care unit, where he was mechanically ventilated. Clinically, the patient worsened further and died on day 5 after admission. Severe HMPV infections are rare. However, patients suffering from hematological diseases are at high risk, which is exemplified in this case report.