The Medellin group is defunct now. There are definitely still functioning drug trafficking networks in Colombia, but I'm not sure if there are still functioning, active "cartels". The cartels in Cali, Barranquila, and the Norte del Valle (an offshoot of the Cali group) are believed to be defunct, as well. The Cali Cartel started to rise to power while Escobar was on the run and eventually killed in the early 1990's; after Pablo's death and the convictions and deaths of many of the other top players in Medellin, the Cali Cartel became the most powerful in Colombia. Once the leaders of the Cali cartel became entangled in legal problems, they made a deal with the Colombian government that allowed some of their soldiers to continue functioning, and that group became the Norte del Valle cartel.

Even if there are cartels in Colombia that are still active and functioning, today they are basically just the suppliers. They don't control the trafficking routes into the United States anymore, nor do they move the product into the States with their own people or have a stranglehold on distribution like they did back in the 70's and 80's. Nowadays, the Mexican cartels basically handle all aspects of transportation, and I would imagine that they also control nearly all of the distribution of heroin and cocaine once it arrives into the States. The Colombian's pretty much just make their money on the front end now (with cocaine).