Gene therapy has made major achievements in the last few decades. These were in numerous medical disciplines, including metabolic, oncologic, infectious and regenerative. As of today, regulatory agencies, both in the USA and Europe, approved for clinical usage numerous gene therapy treatments. However, we are still facing a number of significant obstacles including: 1. Efficient delivery systems, 2. Immunological responses, and 3. recently we have learned that many gene therapy approaches are very expensive. The COVID-19 pandemic was a period in which genetic vaccination had proved its efficacy, by which RNA in a synthetic delivery system was very effective. This review will focus on three fast developing technologies in gene therapy: 1. CAR-T cells, 2. CRISPR-Cas and 3. RNAi.