Given that conventional therapies are ineffective for COVID-19, obtained exosomes from stem cells have been proposed as a sustainable and effective treatment. Exosomes are subsets with lengths between 30 and 100 nanometers, and they can be secreted by different cells. Exosomes are containing different types of miRNAs, mRNAs, and different proteins. The role of immune system modulation of exosomes of mesenchymal stem cells has been studied and confirmed in more than one study. Exosome miRNAs detect and reduce cytokines that cause cytokine storms such as IL-7, IL-2, IL-6, etc. These miRNAs include miR-21, miR-24, miR-124, miR-145, etc. The risks associated with treatment with exosomes from different cells are relatively small compared to other treatments because transplanted cells do not stimulate the host immune system and also has reduced infection transmission. Due to the ineffectiveness of existing drugs in reducing inflammation and preventing cytokine storms, the use of immune-boosting systems may be suggested as another way to control cytokine storm.