2018 marks the 100th anniversary of the 1918 influenza pandemic, which claimed ~50 million lives. The introduction of influenza viruses and subsequent adaptation to humans, which enabled human-to-human transmission, continues to pose a constant threat of a future pandemic. Despite the efforts to develop antiviral drugs and vaccines, improved surveillance and prevention strategies, influenza viruses continue to circulate in human populations and cause seasonal influenza epidemics around the world each year. In light of the rapid evolution of the virus, globalization, the growing human population and the magnitude of intercontinental travel, outbreaks on the scale of the 1918 influenza pandemic would even today have a devastating effect. This collection includes Reviews and Research articles from across the Nature group of journals to showcase the latest advances in our understanding of influenza virus biology, evolution and adaptation, and advances in surveillance and drug and vaccine development.