Resin is a plant extract that contains phenolic compounds and terpenes. Resin is typically bonded with an essential oil produced by the plant and is not water-soluble. Resin is usually sticky and hardens when it is exposed to air.
According to one study, “Terpenoids and phenolic resins have been identified with the former consisting majorly of the internally formed resins while the latter largely constitute resins formed on the surface.” There are many different types of resin. Most resin types have industrial applications, but many of them also have medicinal applications. 
Medicinal Properties of Resin
The medicinal properties of resins are dependent on the plant it is sourced from as well as the terpenes and/or phenolic compounds it contains. Another study on resins says that most of them “are antimicrobial and wound healing in animals and in the plants that secrete them.” Examples of this can be seen in balsam of Peru and pine resin. 
With other resin-producing plants come other effects. “For example, frankincense, the gum resin of Boswellia serrata, is well documented as an inflammation modulator that is helpful in asthma and ulcerative colitis. […] The gum resin of Commiphora molmol (myrrh) is antiparasitic, analgesic, and antineoplastic.” 
Additional types of resin and their applications can be found in the below table. 
What is Live Resin?
Live resin is extracted differently in order to maintain the terpene profile. For cannabis, that process involves freezing the flower immediately after harvesting. No terpenes are lost or degraded, which can happen during the drying and curing stages. This process provides a product that maintains the flavor and scent profile of the plant. It also preserves the maximum health benefits that live in the terpenes and phenolic compounds.
References: Adetunji, O.A., et al. Preparation of Phytopharmaceuticals for the Management of Disorders
The Development of Nutraceuticals and Traditional Medicine. 2021. Doi: 10.1016/C2019-0-01420-3 Yarnell, E. Veterinary Herbal Medicine. 2007. Doi: 10.1016/B978-0-323-02998-8.X5001-X  Parimal, K. Et al. Resins from Herbal Origin and A Focus on Their Applications. International Journal of Pharmaceutical Sciences and Research. 2011. Doi: 10.13040/IJPSR.0975-8232.2(5).1077-85. Cited=6. Journal Impact Factor=0.65