Well you didn’t say what you mean by the “next ISS”. If you mean the next big international space station in LEO, there are no plans at present. But if you mean by this the next big international space project, then I think the ESA village is the best bet for the next one.

It will probably be at the Moon’s north or south pole, at one of the “peaks of almost eternal light” next to craters of almost eternal darkness. The sun will skim around the horizon, and be visible 24/7 nearly all the year round. Temperature near constant. Heat rejection is easy because anything flat on the surface never gets any sunlight on it. Solar power can be collected by a vertical panel that rotates once a month - or mirrors can reflect it to a rover or panel that needs it. They would explore the ice that probably has collected in permanently shadowed regions around the poles. Other missions to the Moon could explore the probably vast lunar caves.

It would be like the ISS but called a “village” because you can have many habitats in a small geographical region, either physically connected or close by. Both China and Russia want to be involved in it. The US is the only major space faring country that isn’t interested at present.

The habitats could share facilities or have separate facilities. Even if some of them are are just close enough to each other to offer help in an emergency, there are obvious benefits in proximity somewhere as hostile as the vacuum of the Moon.

ESA are the ones who are promoting it at present. I think it should be very interesting and the format of a “village” allows a much more flexible approach than the ISS.

I think we are bound to continue to have space stations of some sort for humans in LEO. But they don’t need to be as large as the ISS. China will surely continue with its space stations in LEO, and I’d have thought there’d be some value in habitats in LEO and probably at L1 / L2 as part of the plans to explore the Moon. I think, though nobody is actually planning this, that it would be useful to have some sort of space station in LEO to experiment with artificial gravity and closed systems for space habitats, growing their food etc, with artificial gravity through spinning, perhaps using a tether system. This could be a much smaller, lower cost facility than the ISS. So far there have been no experiments in artificial gravity at all applied to humans.

Also, by the mid 2020s it might be that we get Skylon flying into space regularly, perhaps costs of rocket launches go right down and so on.

Those though are conjectures. The ESA village I think is the only currently planned international space project that is at a stage where it looks like it might actually happen. I think myself that it’s a shame that NASA are not interested in joining in though they may well get involved in a station at L1. Trump has canceled the asteroid redirect mission and his space plan has no goal at all in the Earth Moon system outside of LEO as far as I know. The Moon is the obvious and closest place to visit and hardly explored. Perhaps his administration may eventually get interested in a return to the Moon.

Whether or not, I think by the mid 2020s all the other space faring nations probably will join in building a lunar village. And we’ll see what the US does when that happens. I can’t see everyone joining in sending humans to Mars myself. Not at this stage, though that is what the US wants them to do.

For details, see my Case For Moon First