The HELLO cluster-randomised trial tested whether a simple, multicomponent workplace-culture intervention could reduce burnout among ICU healthcare professionals. The intervention promoted organisational support and positive team interactions through structured messages, email nudges, greetings during morning meetings, role modelling and positive feedback. The international trial involved 370 ICUs across 60 countries. Before the intervention, burnout was common among participating staff. After four weeks, burnout prevalence was lower in the intervention group than in the usual-care group, alongside improvements in measures of emotional exhaustion, depersonalisation, personal accomplishment, job satisfaction, workplace safety and perceived ethical climate. The finding is important because it shifts the discussion of clinician wellbeing from individual resilience alone toward team and system-level factors. The intervention did not require a new clinical technology or major infrastructure investment; it focused on how teams interact and support one another during routine work. This is closely aligned with CritiCARE 2026's humanisation theme and its dedicated sessions on burnout, workforce, communication and critical-care culture. For HCP leaders, the practical takeaway is that psychological safety and positive communication can be treated as operational quality-improvement targets rather than optional wellbeing activities.