SOAP and XML based Web Services aren’t dead yet. I don’t think they will be for quite a while because they are very common in large enterprises (government, banks, telecommunications, etc).
SOAP is basically an XML based API that existed before the REST API existed. SOAP stands for Simple Object Access Protocol – it’s a mostly legacy protocol that was designed for doing remote api requests in a language independent way. From time to time unfortunately, we’ll need to call a SOAP API.