Recently, we've heard that Tom Holland is regarded as a fairly bad security leak when it comes to details of the MCU. The guy has a tendency to talk, so it's not clear whether this added level of security is something that everybody is dealing with or if they have to make things tougher for Holland because they're afraid he'll talk. What does seem to be clear is that there is something or somebody in Avengers: Infinity War that Marvel really wants to make sure we don't know about. Is there going to be an introduction of a new villain in the film or possibly a specific returning character they don't want to tell us about? It's certainly a possibility, but it could also simply be that they're not telling anybody anything in hopes that they can keep as many secrets as possible between now and next summer.