Community-acquired pneumonia (CAP) is the most common infectious disease requiring admission to intensive care units (ICUs), and achieving an early and precise diagnosis of CAP remains a challenge. Biomarkers play an important role in improving clinical judgment in the emergency room and are adjuvant in evaluating treatment responses. Novel biomarkers, such as cortisol, pro-adrenomedullin and endothelin-1, have been shown to be associated with disease severity and short-term outcomes. This review article focuses on the clinical use of novel biomarkers, severity prediction and treatment monitoring as well as future directions of the field.