https://www.pcgamer.com/sekiro-resurrection-mechanic-allows-for-deadlier-combat-than-dark-souls-says-miyazaki/

Sekiro, From Software's next game, subverts nearly everything we've come to expect from Dark Souls, said Steven after a hands-off demo at E3. One major change is its resurrection mechanic, which lets players revive themselves immediately without returning to a checkpoint. And despite how it might sound, game director Hidetaka Miyazaki says this can make Sekiro harder than Souls, not easier. 

Chatting to the PlayStation Blog, Miyazaki says Sekiro's difficulty was designed with the knowledge players can die and resurrect on the spot.