It's not 100% clear if Biden outright won the active duty military vote or not. But all indications from examining the results in areas with a heavy military presence (such as Virginia Beach), reported votes from military bases themselves, and overseas military ballots, are that there was at the very least a massive swing against Trump among the military vote since 2016. He either lost it completely or nearly did, and since he won it by like 20 or 30 points last time, that's a pretty huge drop either way.
iirc some precincts in San Diego that are almost all military went 50-50 or nearly so. And in addition to Virginia Beach, Colorado Springs also swung hard towards Biden.
