Keen Smell. The panther has advantage on Wisdom (Perception) checks that rely on smell.
Pounce. If the panther moves at least 20 feet straight toward a creature and then hits it with a claw attack on the same turn, that target must succeed on a DC 13 (8 + proficiency bonus + STR modifier) Strength saving throw or be knocked prone. If the target is prone, the panther can make one bite attack against it as a bonus action.
Construct Resilience. You have advantage on saving throws against being poisoned, and you have resistance to poison damage. You are immune to disease.
Favored Enemy (Humanoids). You gain a +2 bonus to damage rolls with weapon attacks against creatures of the chosen type. Additionally, you have advantage on Wisdom (Survival) checks to track your favored enemies, as well as on Intelligence checks to recall information about them.
Claws. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 9 (1d6 + 6) slashing damage.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 8 (1d4 + 6) piercing damage.
Coordinated Attack. The panther can use its reaction to make a melee attack when the ranger uses the Attack action on their turn.