。
She's singing the latest hit songs.
Literal
She [topic-は] recent [genitive-の] popular-song [object-を] is-singing.
流行歌 (はやりうた or りゅうこうか) literally 'fashion-song' — a popular hit, the songs that catch on for a season. The reading りゅうこうか is the more written/formal Sino-Japanese, while はやりうた uses the native Japanese reading of 流行 (はやり, 'fashion, what's catching on'). The progressive ~ている here is ambiguous between an ongoing single performance ('is singing right now') and a habit ('has been singing'), and Japanese is content to leave context to disambiguate.