The COVID-19 pandemic caused by the novel Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-COV-2) has put the world in a medical crisis for the past three years, and almost every country, regardless of its developmental status, has been affected by the situation. Nearly 6.3 million lives have been diminished due to the virus outbreak. Numerous in-depth studies of the mechanisms used by SARS-COV-2 have been going on to minimize the consequences of the viral outburst. Angiotensin-Converting Enzyme 2 receptors and Transmembrane serine protease 2 facilitates the viral entry to the host cells, and upon internalization, it uses the host machinery to replicate viral copies and alter the downstream regulation of the normal cells, causing infection-related morbidities and mortalities. In addition, several epigenetic regulations such as DNA methylation, acetylation, histone modifications, microRNA, and many epigenetic factors such as age and sex are responsible for several upstreaming. Down streaming regulations of the viral entry, its immune evasion, and cytokine responses also play a major modulatory role in COVID-19 severity, which has been discussed in detail in this review.