Because of the timely relevance of its anxious comedy, HBO’s Insecure has a hard line on the hippest R&B and rap tunes of its moment. SZA brings the right vibe with the breezy “Supermodel,” while star Issa Rae contributes deeply inspired rhymes in spoken-word tracks like “Go Low" and “Ho For It.” In “Insecure,” Jazmine Sullivan and Bryson Tiller riff on contemporary relationships.