Sylvester Stallone planning and writing a fifth Rambo film

After the huge success of his most recent film, Sylvester Stallone seems to be planning a fifth RAMBO. Stallone revealed that he has started writing the script for the fifth installment of the franchise and also said this one will be a bit different than the previous four.

Stallone told Swedish newspaper Metro,
“I would like to take Rambo to another genre, experiment a little with the character. It would definitely not be another war movie. I can’t go any further with that than what I’ve already done. What it’s going to be like, I’m not going to reveal at this point. But I’m already halfway though writing the manuscript”
[source]