37 years have elapsed since a human being last set foot on the Moon. Had the story continued as many space science pundits predicted at the time, we would have had space colonies there by now, and would be making ready for a manned expedition to Mars. As it has turned out, the political will (and that is what it was to begin with - a political exercise to 'win the race to the Moon' against the Russians) to do that disappeared after the US succeeded spectacularly. Right now there is no nation which has the capability to place humans on the Moon (including the USA).
Lately, there has been a concerted effort to "restart" a (continuous) human presence on the Moon, this time with the USA as only one of the "contenders". Some others are China, Japan, India, and the Europeans, all of whom seem to be at various stages of "fleshing out" the idea. The severe constraints to spending money in this field imposed on the USA by its immense deficits may mean that one of the other nations involved will be the next to land a human being on the Moon.
A continued human presence on the Moon requires the availability of "local" raw materials (the most important being water in either frozen or liquid form). Notwithstanding the comparative proximity of the Moon to Earth, in some respect we know less about the presence of water on the Moon than on the planet Mars. The robotic landers and orbiting satellites which are currently exploring Mars have given us very good evidence that water is present there in sufficient quantities to make human habitation possible.
A first step towards an expedition to Mars (a return trip would take several years) would involve learning about the details of maintaining human life on an extraterrestrial body; the Moon is the closest and most easily reached. There are many ideas about such an endeavour (an example: http://www.geoffreylandis.com/pole.html). It is important to have the necessary resources wherever humans may find themselves. To that end, the US is preparing to send some orbiters back to the Moon to explore specific areas - particularly the north and south poles where there are some spots which have eternal sunlight (for energy to supply a human settlement), and perpetual shadow (for possible water ice). For all the lunar observations which have taken place over the past four centuries or so, both from Earth and by lunar rovers, humans on the Moon, and samples brought back from there, we know little about what may be found at the lunar poles.
Another of the concerns to be addressed in any extraterrestrial human undertaking is how to deal with illness. While we are far from knowing all the answers, I feel that medical science here on Earth has made tremendous strides since the time of the Moon landings. As an example, our son's fight with cancer is certainly helped by the availability of drugs which did not exist at that time (as his parents, of the greatest importance to us). This is one area where progress has been greater than predicted.
I have a hope that I'll see more Moon landings in my lifetime, and, with luck, even a landing on Mars. Personally, the closest I can come to a "landing" is to look through my telescopes, and to use the internet links which keep me up-to-date in that regard.