PolymorphicComposition.scala

def translate[F[_]: Monad](app: Http[F]): Http[F] = for {
  resp <- app
  tx <- Kleisli.liftF(Translator[F](resp.body))
} yield resp.copy(body = tx)

def hello(theUri: Uri): HttpRoutes = HttpRoutes.of {
  case Request(POST, uri, name) if uri == theUri =>
    Future.successful(Response(OK, s"Hello, $name!"))
}

val es = translate(hello(Uri("/hola")))
// <console>:37: error: could not find implicit value for evidence parameter of type cats.Monad[OptionFuture]
//        val es = translate(hello(Uri("/hola")))
//