This is because there is a chance that he could be working with famed Japanese horror mangaka artist Junji Ito on the game. While the details have yet to be announced, Ito himself had confirmed that he has been having conversations with Kojima, and that he was invited to work it with him.
According to Ito, “I do know director Kojima and we have been in conversation that he may have a horror-based game that he may be doing, and so he has invited me to work on that, but there are no details on it yet.” It was also revealed that during the development of Silent Hill, Kojima back then had wanted Ito to work as a concept artist, but given that the game was ultimately shelved, that obviously did not come to pass.
Kojima has since released Death Stranding as the first title under his Kojima Productions company. It is unclear what new games he could be working on, but if you’re a horror fan, then this upcoming title, whatever it is, with Ito could be worth keeping an eye out for.