Dungeons & Dragons excels at taking a simple ruleset and providing endless opportunity for imaginative gameplay, but some of its mechanics can be tricky. Figuring out how 5E's damage immunities, resistances and vulnerabilities work goes from straightforward to complicated in a hurry, so some players may need help. Knowing the ins and outs of how these rules work can make the difference between an all-star player character saving the day and a grueling battle that players won't enjoy at all.
Source：https://www.cbr.com/dnd-immunities-resistances-vulnerabilities-explained/
