Summary: The pandemic of COVID-19 disease caused by a novel SARS-CoV-2 coronavirus, which emerged in China in December 2019 and quickly spread across the globe over the ensuing weeks, has prompted the scientific world to step up research into coronaviruses. While, over the past two years, scientists have developed effective vaccines and new drugs against SARS-CoV-2, the body's immune response during COVID-19 still remains a challenge. In this review, the current state of knowledge on the immunological mechanisms involved in the various stages of SARS-CoV-2 infection and their further clinical implications have been presented.