Mars exploration has long been driven by the hypothesis that the planet once possessed or may still host life. Early observations of seasonal polar ice caps and the mistaken identification of canals strengthened pre-space-age expectations of habitability. However, modern missions have revealed a hostile present-day environment characterised by intense radiation, extreme cold, low pressure, and chemically reactive soils. The Viking missions conducted the only direct life-detection experiments, producing ambiguous results that could not conclusively confirm biology. Subsequent missions shifted focus toward identifying past habitability, particularly through evidence of water, organics, and favourable geochemical conditions. Studies of terrestrial analogues and extremophiles demonstrate that life can persist in environments similar to ancient or subsurface Mars. Despite promising indicators such as methane variability and potential microfossil-like structures, definitive evidence of Martian life remains unconfirmed, necessitating futuresample-return missions and advanced analysis.