It's no secret that Sony really regretted letting Demon Souls go as an exclusive game. The company simply didn't see the potential in what would become Dark Souls. This was rectified when the company announced Bloodborne at E3 in 2014, a game that went on to sell millions of copies.
The game was a critical and commercial darling and a sequel is inevitable. Now, given that it was only released in 2015, it may be too soon for a sequel but From Software are really good at quick turnarounds and I wouldn't be surprised to see a trailer for a sequel with no release date. As they say in the sister series, "Prepare to Die".