It was at one point a fully-fledged country, now it's listed by the UN as an "occupied territory". i.e. Morocco invaded and have taken over. They're adamant it's simply Morocco, and they get really mean to anyone that says otherwise, or even if you have a map that shows it as a separate country.
Driving through it's just like you never left Morocco, except there are military roadblocks every 100km, there is a lot of new construction, and gas is noticeably cheaper than the rest of Morocco (i.e. Morocco attempting to spur development and help "claim" it)
It's fascinating to me a country can be invaded and occupied by their neighbor and the world does nothing about it.
And there's a place on earth no country wants: https://en.wikipedia.org/wiki/Bir_Tawil
See also: Palestine
Western Sahara was never a sovereign, recognized state. Spain relinquished it's colonial claim over it and Morocco and Mauritania rushed to claim parts of the territory (Mauritania has since renounced too).
The closest thing to a nationally representative organization was the Polisario Front, a military-political structure based on ethnic Sahrawi affiliation. It didn't help that the area is so sparsely populated and could barely sustain an independent state in the 70s, let alone a state capable of withstanding the territorial advances of such a powerful neighbor like Morocco.
Is this a case where the colonial power should have been more firm when drawing arbitrary lines in the sand? The opposite of what they usually get criticised for.
The political situation is also pretty stable there since the late 70s. Shit, but stably shit.
The main reason that most countries refuse to recognize Somaliland is that the current thinking is that letting it be independent would harm the process of putting Somalia back together again after it fell apart in 1991.