Sugar-free candy and gum usually mean xylitol (see above) — deadly. Sugared versions are "just" obesity and GI upset, plus wrapper obstruction.
Same rules; keep all candy away.
It is the xylitol, not the sugar, that kills.
Sugar-free product + dog = assume xylitol and call the vet.
ASPCA Animal Poison Control: (888) 426-4435 · Pet Poison Helpline: (855) 764-7661 — 24/7, a fee may apply. Your own vet first when reachable.