Capcom has trademarked a brand new Monster Hunter game recently. This trademark points towards a game release so if we go by the earlier rumors, there is a good chance that this might point towards a potential Monster Hunter for the PS4.
In case you have missed the previous rumors, Monster Hunter for the PS4 was rumored by a 4chan leaker who correctly leaked the names of Monster Hunter XX and a potential Monster Hunter XX announcement for the Nintendo Switch. The leaker also stated that Capcom will release an exclusive Monster Hunter for the PS4 that he recalled as being the next mainline Monster Hunter game. He called it Monster Hunter 5 and revealed that it will be open world Monster Hunter game that strays away from the norms of the series and aimed more at the casual crowd.
The recent trademark for Monster Hunter is for a game called Monster Hunter World and it was filled by Capcom just a few days before E3. While there is no confirmation of the trademark being for a possible PS4 game, we can only hope and go by the rumors that it is indeed the case. Deep Down was also a game that was leaked through trademark by Capcom and it turned out to be the real deal, so we will just have to wait and see what happens with Monster Hunter World.