Progress means your opponent's effects simply don't touch this Digimon while it's attacking, security effects included. That turns every swing into a clean math problem of DP versus DP, with no bounce, no deletion, no de-digivolve mid-attack. Finishers with Progress are the ones you point at a full security stack, because the usual defensive tricks just don't fire.
16-39-1. <Progress> is a keyword effect that reads "this Digimon isn't affected by your opponent's effects while attacking." 16-39-2. <Progress> is a persistent effect. (For details, refer to 15-8-2 "Persistent Effects") 16-39-3. <Progress> will activate while the Digimon with this effect is attacking.
Comprehensive Rules §16-39 — official rules page
Public lines whose key cards carry this keyword, step by step.
9 cards carry this keyword:
Rule text © Bandai, quoted from the official Comprehensive Rules for reference. Combalo is not affiliated with Bandai.