Sekiro: 11 MAJOR Changes That Will Shock Dark Souls Fans
7. Stamina Is Gone
Either stamina is the one great force governing the heart of PVP or Soulsborne combat in general, or it's been a weight around Soulsborne games for a decade, and the one thing stopping even more frenetic altercations between you and an opponent.
FromSoftware clearly think the latter, and stamina is now gone completely. You do have the new Poise meters dictating when you or an enemy's guard is about to break entirely, but you're free to attack to your heart's content, knowing you can dodge/evade as much as possible and take to the rooftops to regain health or take a breather.
I will point out that your own poise meter doesn't drain when attacking, so if you're keeping the pressure on and fighting back immediately after blocking a flurry of blows, wading in too fast and then getting caught out will see your guard broken immediately.
This is the nearest Sekiro comes to mimicking the stamina use of old, but you're free to dodge, evade and move around the battlefield as much as you see fit.