There's a sick park in Cali called Calida, I think. The best park I can remember skating in Colombia was in Cartagena. I spent most of my time in Bogota which, unpopular opinion, I prefer it over Medellin.
Generally speaking, I enjoy Colombia and if you have plenty of extra time to skate then take your board. Just keep an eye out because it's definitely a different kind of sketchy. Last time I was in Medellin my cab got pulled over otw to the airport for no reason and the cops searched us down pretty hard. Fortunately they didnt' steal anything or try to get a bribe - at least not from me.