Quran mentions several groups of people such as Muslims, Jews, Christians, etc. It also gives character traits of these groups. An important point to consider is that when Quran mentions for example ‘Jews’ it means those people who act according to traits given in Quran for Jews, and not by what the world calls them or not by what label they put on themselves.
And when Quran mentions ‘Muslims’, then those people who match the character traits of ‘Muslims’ in Quran are meant. The labels that people put on themselves don’t matter. If some people call and label themselves as ‘Muslims’, however, their actions actually match the traits of ‘Jews’ given in the Book, then they are actually ‘Jews’ in the eyes of the Lord. Vice Versa, if some people call and label themselves as ‘Jews’, however they do not match the characteristics of ‘Jews’ in the Book, they are not ‘Jews’ in the eyes of the Lord.
With this point in mind, the link to below post reviews some of the character traits given in Quran for groups to see if we can recognize groups by their behaviors.