3:16 PM PT -- Looks like Kanye was out there playing new music during his Miami outing ... including that new Backstreet Boys-sampled song he's been teasing this past week.

A fair amount of the track was played during what appears to be an impromptu listening event out at Art Basel ... and it sure sounds pretty catchy. We know Ye's got this new album he's been working on lately, and from the looks of it -- he may be close to done.

Kanye West and his wife, Bianca Censori, are back in America -- and they hit up Art Basel together this weekend, where BC was showing off her assets ... with a see-through getup.

The couple was spotted strolling around casually Sunday at one of the art galleries on display in Miami right now -- taking their time to check out the artwork and maintaining somewhat of a low profile, it seems ... which you can see in this video, obtained by TMZ.

Check it out ... Ye's got his whole head covered up like he usually does these days, and Bianca was in as revealing of an outfit as we've seen her in over these past several months.

Indeed, it looks like her breasts were on full display ... nipples out and everything. Of course, she didn't have a care in the world about it -- and nobody around them appeared to bat an eyelash either. Like we said, it's almost as if most of the folks here didn't recognize them.

Anyway, eyewitnesses tell us it was just Ye and Bianca rolling with a few security guards -- no larger entourage from the looks of it. We're also told it didn't appear that they spoke to anyone ... not even each other as they walked around.

Couple takeaways ... for one, Ye's back in the States, which is interesting considering he's been away from a long, long time now -- be it in Europe or the Middle East. Also, Bianca's also very clearly back in his orbit ... this after being out of the picture for a hot minute.

Just like old times ... eh, Ye?