Running can conflict with muscle gain if your heart rate remains too elevated. If you want to lose the fat while gaining lean tissue.
Cardio should be performed below your first ventilatory threshold.
That means you should be able to speak comfortably while performing cardio. And so this for 30 to 60 minutes, as often as you can. I do either fast walking or ...
Running may reduce the effect of strength training of legs.
In order to reduce this interference effect you should (1):
keep your running sessions short (< 45 minutes)
have as much time as possible between running and strength training (of legs)
run slowly or even better walk
Walking for cardio is what some bodybuilders do.
However for a runner this is ...