I'll start by saying that I think all the Exos are close to each other to a very significant extent. However, there seem to be some Exos who regularly meet up outside of group events (or work) which I'll highlight as being 'closer'.

Known to Hang Out Regularly Outside of Work:
- Junmyeon and Sehun: As the two who returned to living in the dorms together for some period during 2022 and perhaps beyond definitely see each other outside of work.
- Baekhyun and Sehun: Seen together during Baekhyun's enlistment going out to various events/galleries
- Chanyeol and Sehun: Have referred to hangouts together
- Chanyeol and Kyungsoo: Between boxing classes, trips to Japan and more, we've heard a lot about them hanging out together.
- Sehun and Minseok: During the Brand New promotions, Minseok talked about seeing and hanging out with Sehun.
- Sehun and Yixing: Sehun has talked about calling Yixing while Yixing has talked about seeing Sehun ahead of his enlistment.
- CBX: All three seem to hang out, in pairs as well as as a trio. Minseok and Jongdae in particular have been known to go to restaurants together and said during the filming of Hear Me Out that they hang out together a lot outside of work.
- Chanyeol, Junmyeon and Jungian all go to the same gym and workout together sometimes.
- Chanyeol, Baekhyun and Sehun have the same voice teacher.
- Sehun and Kyungsoo have been seen hanging out together.

As the members themselves have said, Sehun is a bit of a social glue and is one of the most likely members to organize get togethers and one on one time which you can see is also reflected above.

The members have always been supportive of each other's projects and often attended their solo events or their shoots. They've also gotten food /coffee support trucks for each other. Some like to use IG to comment on each other's posts.

Ultimately closeness is always difficult to discern from the outside looking in, especially with Exo who care a lot about keeping their private lives private. There's duos who are clearly very close like Junmyeon and Baekhyun who nonetheless have such a busy schedule that they don't seem to hang out much outside of work but might call or visit each other at their schedules. Obviously we don't get to hear a lot about Yixing's current relationship with the members beyond his relationship with Sehun and his IG likes and follows. I've also kept this 'closeness' analysis to 2020 onwards even though we know Chanyeol and Jongdae hung out several times outside of work in 2019. My recommendation is to not focus on who is more or less close but to instead pay attention to the interactions between your two favourite members/your favourite duo because you're sure to notice details about their relationship if you do. Exo loves Exo. We are one.