Because "ytcinema" is a common shorthand, it may refer to several different projects: YouTube Cinema by CheeseFrog/Houbo:
"Yeah, and what if we could also discover new content, connect with other fans, and discuss our favorite shows and movies in real-time?" Jack added.
If you want to watch a specific movie, consider legal free alternatives (Tubi, Pluto TV, Freevee, YouTube’s own free-with-ads movies) first. YTCinema carries significant digital hygiene risks.