TREM1 and pneumonia: The soluble form of TREM-1 (sTREM-1) has emerged as a leading marker for its ability to discriminate between those at risk of morbidity and mortality, those with uncomplicated infection across a range of infections (e.g., pneumonia, malaria, COVID-19, sepsis, dengue), and populations (e.g., adults, children, low- and middle-income countries, high-income countries) [8,10,26].