Mankind is every single human being — all of us. The discovery of cures for diseases benefits all of mankind, while global warming is not so kind to mankind.
The entire human species can be referred to in one simple word with mankind. Pollution is something that harms mankind across the globe, and disasters like war and famine have affected mankind all through our history. If you think your dad's brownies are the very best in the entire world, you could exaggerate a little and say, "They're the most delicious thing known to mankind." In its Old English origin, man is gender-neutral, meaning simply "person."