Hunter's Lore is a Ranger feature gained at level 3 in the 2024 SRD. You can call on the forces of nature to reveal certain strengths and weaknesses of your prey.
You can call on the forces of nature to reveal certain strengths and weaknesses of your prey. While a creature is marked by your Hunter's Mark, you know whether that creature has any Immunities, Resistances, or Vulnerabilities, and if the creature has any, you know what they are.