its why I dont like calling it scifi to people on suggesting it, because it kind of spoilers the premice on the idea how humanity got to that position in the first place. Its better advertised as fantasy mystery, than scifi.

back when Shin Sekai Yori aired, the yaoi jumpscare of Episode 8 caused a lot of people to drop the (very good) sci fi anime.

On and off conflict between the two countries for a while now. From what i know:

the land in dispute is Khmer land built an entire millenia ago under Suryavarman.

Thailand claims the lands were there due to drawn maps during 1904 french colonia indochina times. Cambodia claims the International Court of Justice lines in 1962, as about a decade ago, france pulled out of the region, and thailand moved in to occupy it.

to quickly summarize a lot, Thailand eventually obliged and ceded the temples to Cambodia. Cambodia went through the civil war. Thailand goes through a military coup, and expels a bunch of refugees into the region.

fast foward to 2008, globally wanted to turn the temples to a world heritage site. map draws borders around the site without giving posesion to a country, Thailand renegades on the plan but Cambodia continues.

Since 2008, there have been conflicts from both sides, and nations globally are trying not to exacerbate the issue.