Hmm... honestly, I don’t think it=それ.
It could be それ but it could be あれ. It’s depends on context. And we often skip to translate “it’s”. For example, if you want to translate “it’s rainy”, translate part is only “rainy”.
The simplest answer is “how far from speaker”.
これ=this, それ、あれ=that. Just あれ is farther than それ. This one is easiest to understand.
Also, we use それ, when the thing is closer to listener. So if parson A is sitting next to B, then if A has a pen, A say “これはペンです。” If B has the pen, A say “それはペンです。” And if it’s far from A and B, A say “あれはペンです。”
So, back to the first paragraph. I wrote “it’s depends on context.”
For example, if A saw B is eating sushi then if A say “I love it.” That means “わたしはそれがだいすきです。” if A traveled Japan and A ate sushi. A talk about sushi that he ate in Japan. “I ate sushi. I love it!” That means “わたしはすしをたべました。あれがだいすきです。”
あれ sometimes use for things you can’t see now. Like your memory or different areas... etc.
I hope this comment help your Japanese study.