Gain 20% of Physical Damage as Extra Chaos Damage against
Poison you inflict with Critical Strikes deals 50% more Damage
+0.4% to Critical Strike Chance per Poison affecting Enemy, up to +2.0% 
Toxic Delivery is a notable Ascendancy passive skill for the Assassin. It grants damage reduction against damage over time, more poison damage to poison that was applied with a critical strike, added critical strike chance per poison on an enemy, and extra physical-to-chaos damage against poisoned enemies.