The more advanced society uses technology similar to that of today but with a understanding of genetic engineering. The more advanced society uses mostly uses guns & grenades but roughly 1/3 of them are equipped with melee weapons. They have giant humanoids, most about 1.5x as large as a normal human & few the are about 3x as large as a normal human. They wear heavy leather suits. Their primary methods of transportation are helicopters & trucks. They don't have any armoured vehicles 3/5s of them bleed yellow rather than red.
The more advanced people only rarely show up. When they do show up its mostly to kidnap or kill certain people. They live on a continent that the less advanced society can't access. The few permanent bases they do have in areas the less advanced civilisations access are to extract resources that the less advanced societies don't have much use for, outside of copper.
The less advanced societies have a level of technology similar to that of 50bc Europe. Outside of some basic telegraphs. Their are a few large nations & many smaller nations for the less advanced societies. They can't do much to the more advanced society. Both societies consist of humans outside of the more advanced societies giants.
The advanced culture doesn't intervene beyond the above & avoids contact with the less advanced ones where ever possible. The less advanced cultures aren't able to get any of the more advanced societies things. How would the more advanced societies activities affect how the less advanced ones think? With the less advanced societies seeing things far beyond how advanced the are.