Acute respiratory failure (ARF) is the leading cause of intensive care unit (ICU) admission of immunocompromised patients. In the early 2000's, two randomized controlled trials suggested that noninvasive ventilation (NIV) could decrease mortality of immunocompromised patients admitted to ICU for acute respiratory failure (ARF) as compared to standard oxygen therapy (O2). However, the benefits of NIV in immunocompetent patients with ARF are debated. High flow nasal cannula oxygen therapy (High-Flow Oxygen) may offer an alternative in hypoxemic patients and we recently found in a randomized controlled trial including 310 patients with ARF that High-Flow Oxygen decreased mortality as compared to NIV . In our unit, High-Flow Oxygen is increasingly used in our unit gradually replacing the use of NIV.