Katty is a Colombian paramilitary member and Cassandra is a Venezuelan member of the Tren de Aragua gang (literally, those are their nationalities, lol), so they fight over territory, killing each other and desecrating their corpses.
The tables turn in the final scene. Katty takes off her boots to rest her feet, but Cassandra strangles her to death. Finally, a special forces agent intervenes and mercilessly strangles her despite her pleas.