A major cause of respiratory tract infections in infants, adults, the elderly, and people with impaired immune systems is the human metapneumovirus (HMPV). The Paramyxoviridae family was replaced by the Pneumoviridae family in 2016. The genetic groups A and B that make up this virus are further subdivided into subclasses, with A1, A2, B1, and B2 varying from year to year. Originally identified in the Netherlands in 2001, HMPV has since spread throughout the world. Droplets from infected people’s respiratory systems are the main way it is transmitted. Although HMPV infections are often mild and self-limiting, they can have a complex clinical course in immunocompromised patients and the elderly. The diagnosis is primarily relied on a nucleic acid amplification test, such as reverse transcriptase polymerase chain reaction (RT-PCR) which is the gold standard for modern molecular diagnosis because of its higher sensitivity and specificity. However, because it requires specialized laboratory equipment that not all healthcare facilities have, RT-PCR is not as commonly used. While promising, other diagnostic techniques including next-generation sequencing and antigen detection assays are not yet widely used in clinical settings. All of the current HMPV therapy modalities offer a limited range of choices. Preclinical tests of novel techniques to monoclonal antibody creation have showed promise, but human testing is necessary to determine their safety and efficacy. There is currently no vaccination, and the available treatment is supportive. Nonetheless, current study yields positive findings. In this review, we highlight recent advancements in treatment, adult infections, and the structural features of known antigenic sites on the HMPV proteins.