It is interesting that the UK government actually provided far more detail in their warning than the US or Canadian governments did in theirs:
"The Mexican government makes efforts to protect major tourist destinations like Cancun, Playa del Carmen, Cozumel, Los Cabos, Puerto Vallarta and Nuevo Vallarta and these areas haven’t seen the levels of drug-related violence and crime experienced elsewhere. However, there were shooting incidents at a nightclub in Playa del Carmen on 16 January 2017; at the state prosecutor’s office in downtown Cancun on 17 January 2017; and 2 shootings in downtown Cancun on 14 March 2017. There was also a shooting on Palmilla Beach in Los Cabos on 6 August 2017. There is currently an increased police presence in the Cancun area, including in the hotel zone. If you’re visiting any of these areas, you should follow the advice of the local authorities and your tour operator."
https://www.gov.uk/foreign-travel-advice/mexico/safety-and-security