What Build Muscle Also Retains Muscle
If the goal is fat loss, the general consensus is to train a metric shit-ton and make yourself hate life and exercise till you can't feel the left side of your face. While I can respect the sentiment, it's a faulty approach with regards to fat loss.
Fat loss plans should alternatively be referred to as "muscle maintenance" plans. The idea should be to maintain or keep as much muscle as possible while in a caloric deficit. The easiest way to do so is to lift heavy things – remind the body to hold on to precious lean tissue.
To that end, traditional strength training should still be prioritized even if fat loss is the main goal.
This isn't to say you can't help expedite the process with some strategically placed circuits/HIIT/or metabolic finishers. However, if you've already ensured a caloric deficit via nutrition, adding in copious amounts of training volume via high(er) rep sets and endless metabolic conditioning is usually nothing more than a one-way ticket to Crankypantsville and sacrificing muscle.
Don't forget to lift appreciable weight. Force the body to keep your hard-earned muscle.