2015 MacBook Pro warranty from Apple store?

Something else they may have neglected to tell you......the 2015 model is considered "Vintage" which means repairs are only possible as long as the necessary part is still available. This includes any 90 day warranty repairs.

Apple OEM batteries are usually very good so like @Grant mentions, if it makes it 90 days it will probably last for at least a few years.

I had my wife's Ma=cBook pro 2015 battery replaced recently, and raised the same question.

"ALL Apple repairs come with a 90-day warranty. That's the standard policy."

After anguishing over that for a while, I settled on this way of looking at it:

If the battery lasts 90 days without collapsing, it is extremely likely to work for years.

Yep. I had to replace the logic board on my 2016 13" MBP and it was $592 with a 90 day guarantee. That was three years ago