Coronavirus disease earlier known as “Pneumonia of unkown etiology” has emerged as a 6^th public health emergency of international concern. It is a new public crises threatening the world with its infectious nature owing to its rapid transmission. COVID-19 is the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus structurally similar to its ancestors by SARS-CoV and the Middle East respiratory syndrome coronavirus (MERS-CoV) responsible for the viral epidemics in 21^st century. COVID-19 virus is reportedly much more virulent than either the SARS or MERS virus. Its ability to cause serious consequence contributing to the nature of the virus, its pathogenicity and host immune factors. Based on the published evidence this review aims at providing comprehensive summary on microbiology of SARS-CoV-2, virulence, immune pathogenesis, associated pathophysiology. It’s an attempt to aid the health care workers in containing the pandemic, offering novel insights, potential therapeutic targets for combating the SARS-CoV-2 infection and provide reference for future studies.