In English, gender pronouns are gender identifiers for the third-person singular. In the past, gender pronouns were separated into masculine (he/him/his) and feminine (she/her/hers). This separation of masculine and feminine is called gender binary and only recognizes men and women. Many people identify outside of the gender binary. Gender-neutral pronouns such as they/them or xe/xer/xers allow individuals to use pronouns they feel fit with their identities.
Resource: https://academicguides.waldenu.edu/diversity-inclusion/pronouns