it's a thing as of a new spinoff series Law & Order: Organised Crime

Basically he walks back into New York after 10 years of half being undercover and half being in a task force in Calabria, and in the first episode the mob gives his wife the IRA treatment when he was the intended target (or the whole family was meant to die, but only the wife did)

He goes into absolutely hectic revenge mode and most of the underlying subplot is him continuing to straddle the line between remaining a cop (given his previous complaints of going over the top/police brutality) and basically becoming John Wick