If it’s for a block that you are editing in the context of a content node, you need UMB_CONTENT_WORKSPACE_CONTEXT:
import { UMB_CONTENT_WORKSPACE_CONTEXT } from '@umbraco-cms/backoffice/content';
this.consumeContext(UMB_CONTENT_WORKSPACE_CONTEXT, (context) => {
//If you just want it one-time
//This does not react to name changes
const name = context.getName()
//If you want to be kept up to date of changes, you need to
//observe it!
this.observe(context.name(), (name) => {
//This is called every time the name changes
});
}