use monad transformers for great elegance!

getConfirmableFromToken.scala

import cats.data.OptionT
import cats.implicits._

/* 
 * in my domain, the confirmation algebra provides Confirmable,
 * which is parameterized over the type of id of the thing, probably
 * a user, to be confirmed, and the type of the confirmation token
 */

type C = Confirmable[UUID, SecureRandomId]

def getConfirmableFromToken(token: SecureRandomId): OptionT[F, C] = for {
  (userId, confirmation) <- confirmationService.getByToken(token)
  user                   <- userService.find(userId)
} yield ConfirmableUser(user, confirmation)

OptionT[F[_], A] is a monad transformer, representing F[Option[A]], where F represents an arbitrary functor (or monad, because monads are just composable functors!), and A is some type of thing wrapped by that functor, e.g. OptionT[IO, User] encodes IO[Option[User]]. Monad transformers compose neatly and with them you can avoid some boilerplate around monad composition with .flatMap and .map

For more information on this particular implementation of OptionT, see the Cats documentation: https://typelevel.org/cats/datatypes/optiont.html