When you have two pods with different labels, let’s say one with two labels a=something and b=other, and the second one with label b=other, when you use kubectl to get them there is a difference in the way that the -l selector is used.
kubectl -n namespace get pods -l a=something -l b=other it will give you back both pods as it works as an OR operator.
If you wanted to get only the first one that has both labels, but not the second, you would need to use it as in
kubectl -n namespace get pods -l a=something,b=other.
In other words the comma separator acts as a logical AND operator in selecting the labels.