Not sure if you've check a dictionary, but I can see how this might confuse you even after you've looked up this phrasal verb. "Factor in" is usually found in the dictionaries defined as transitive. For instance, Cambridge defines "factor in something" as:
to consider information, esp. as something that might influence a result:
It’s going to feel like 110° there when you factor in the humidity.
However, this phrase is commonly used intransitively as well.1 And yes it means "to be considered/included/figured in, be part of". Some examples:
That type of attention may factor into why so many of the show's relationships have ultimately failed. (CNN)
If Biden holds his current leads in Arizona, Michigan, Nevada, and Wisconsin, the Pennsylvania cases would not factor into the presidential election’s ultimate outcome. (The New Republic)
A couple other phrases share similar meanings. Personally, I am more likely to use "figure into" or "enter into" in these sentences.
1 In Japanese grammar, it'd be 自動詞, except that in Japanese the transitivity binary comes in verb pairs, while in English a verb or phrasal verb can be both transitive and intransitive, depending on the context.