Which is the most deadliest pandemic in the world

Smallpox is considered the deadliest pandemic in human history, having caused an estimated 300-500 million deaths throughout its existence before being eradicated in 1980 through vaccination. While influenza (particularly the 1918 Spanish flu) was devastating (50 million deaths), and AIDS has caused millions of deaths since the 1980s, neither matches smallpox's cumulative death toll over centuries. Swine Flu (H1N1) was a relatively recent outbreak with much lower mortality.