Werewolf Pack Leader — ruling 1

The last ability will overwrite any previous effects that set Werewolf Pack Leader's power and toughness to specific numbers. Effects that otherwise modify its power and toughness will still apply no matter when they took effect. The same is true for +1/+1 counters. For example, if you cast a spell that gives Werewolf Pack Leader +1/+1, after that resolves it is a 4/4 creature. If you then activate its last ability, it will be a 6/4 creature.

Werewolf Pack Leader : règles, fonctionnement et interactions (MTG)

Werewolf Pack Leader is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Pack tactics — Whenever this creature attacks, if you attacked with creatures with total power 6 or greater this combat, draw a card. : Until end of turn, this creature has base power and toughness 5/3, gains trample, and is a Werewolf.

How it works : Werewolf Pack Leader

Original English text — Wizards of the Coast / Scryfall

#1July 23, 2021· Wizards of the Coast
The last ability will overwrite any previous effects that set Werewolf Pack Leader's power and toughness to specific numbers. Effects that otherwise modify its power and toughness will still apply no matter when they took effect. The same is true for +1/+1 counters. For example, if you cast a spell that gives Werewolf Pack Leader +1/+1, after that resolves it is a 4/4 creature. If you then activate its last ability, it will be a 6/4 creature.
No other card is named in this ruling.