In July 1969, Neil Armstrong stepped out on to the lunar surface, and became the first human being to walk on the Moon.
Less than four years later, In December 1972, Eugene Cernan stepped up into the Lunar Module, and (as of February 2018) no human being has walked on the Moon since.
When will the next human being walk on the Moon?
This question will resolve as the date and time (UTC) when the next human has set foot on Earth's moon. If this feat has not occurred between January 1, 2018 to January 1, 2100, this question will resolve as Ambiguous.
By "human", we mean for the purposes of this question a biological human who could reproduce healthy children with a 2018-era human being (ie. excluding emulated consciousnesses, significantly genetically engineered humans, or artificial intelligences).