Synthetic mRNA and the expression of therapeutic proteins have accelerated vaccine development to prevent infection and heralds a new era in targeted immunotherapy in oncology. Therapeutic mRNA vaccines rely on available tumor tissue for gene sequencing analysis to compare the patient's normal cellular DNA sequences and those of the tumor. Carrier-based mRNA vaccines for cancer immunotherapy are now in development that use delivery systems based on peptides, lipids, polymers, and cationic nano-emulsions. There have also been recent developments in dendritic cell-based mRNA vaccines. For patients with available tumor tissue samples, it is possible to develop mRNA vaccines that result in the expression of tumor antigens by antigen-presenting cells (APCs), resulting in innate and adaptive immune responses. Ongoing developments in mRNA immunotherapy include modifications in the route of administration and combined delivery of multiple mRNA vaccines with checkpoint inhibitors. This Editorial aims to present a brief overview of how mRNA immunotherapy may change the therapeutic landscape of personalized medicine for patients with solid malignant tumors.