if you ever see DK facing towards you in the air, get up and shieldgrab. Their only mixup is sideB, which although does some good shield damage, you can still get a grab most of the time.
camp hard, avoid going offstage v. DK.
cargo spike will work ONLY at really, really high percents, which you'll need to tech. Otherwise just hold up and you should be fine.
avoid upB gimmick maneuvers, if they come in low, they have almost no landing lag onstage, and if it's on YI, the entire animation is invincible with that glitch.
DK's fsmash is fairly punishable on whiff/shield
DK punch on the other hand, isn't so much, it also has a hitbox behind him (pretty strong too), so don't bet on a roll or landing behind him to save you all the time.
DK ground pound can be annoying, give him some space and continue camping, expect to almost always take damage landing near DK lol, he's very good at catching snake's landings (in general).