Well, that depends on what they mean by "entities."
I would imagine those are the aliens. They may not look humanoid (I hope not) but they will be some sort of intelligent alien life form that is capable of interacting with humans. I don't think that term means inanimate objects or weather events or whatever else you think it might refer to.
So basically, it's some alien intelligence making contact with humanity or maybe just making their presence known after years of doing the whole UFO/abduction thing, and where the story goes from there, who knows.
Since it's AMC, I'm just hoping it will be surprising.
Again, I'd cite The X-Files as a counterexample. Or Lost in its early seasons. The story could be about the characters trying to cope with the mystery of these entities or the effects they inflict for inexplicable reasons.
There were various alien/supernatural characters in both cases that showed up as actual characters in the drama in both cases.
The X-Files is a UFO drama; V is a first-contact drama. They're more or less opposing ways of approaching the "alien visitation" trope.
They're not all that different. Both are about first contact with aliens, in the sense that they aren't the second contact or the ninety-fifth. They have aliens who appear as characters in the story. The X-Files
pussyfooted around because they needed to maintain some kind of mystery to drag out the story. V
just dumped the aliens right onto us, in the remake anyway, which probably helped kill the story because then the writers had to spin out various motivations and goals for the aliens, which became stupid and incoherent.
Here's hoping AMC will avoid the twin threats of stalling out the story through too much mystery or making the story inane by too little mystery.
You can make up whatever definitions you want for things, it doesn't really matter to me. Discussions on that basis are a pedantic waste of time.