The Sackler family owns Purdue Pharma, the creators of OxyContin, by which they played a major role in creating and profiting from the ongoing opioid crisis. In addition to aggressive marketing, they misled the public about how addictive these painkillers are, and even went so far as to outright deny how addictive OxyContin is.
This immunity protects them from any civil legal claims in exchange for a fine up to $6 billion, part of which will be dedicated to addiction treatment, and part of which will be paid out to those impacted by the opioid crisis, with payouts ranging from $3500 to $48,000.
In addition to the creation of OxyContin, prior to legal proceedings and this fine, Purdue Pharma also opened addiction treatment centers (for profit) to treat opioid addiction.
In light of the damage caused, I think this is such a miniscule consequence, especially when I think of those spending significant amounts of time incarcerated for doing less damage as it relates to drug-dealing.

