The identity & status of Pontius Pilate's successor as commandant of Roman forces in Judea & Samaria is uncertain. Josephus says only that Vitellius, the governor of Syria, dispatched his friend Marcellus "to take care of the affairs of Judea." This may mean either that Marcellus assumed Pilate's position as military prefect for that province or that he was in charge of a limited police action to preserve public order after Pilate had been recalled to Rome. Later in recounting Caligula's  appointment of Agrippa as king of his uncle Philip's tetrarchy (37 CE), he states in passing that the emperor himself sent a certain Marullus as "cavalry commander" [= prefect] of the Jews. It is generally assumed that the latter's tenure lasted until Claudius transferred control of Judea & Samaria to Agrippa I (41 CE). However, since Josephus fails to ascribe any specific action to Marcellus or Marullus or to refer to the departure of either before a successor assumed control, whether these were actually distinct individuals & how long each served in Judea can never be more than educated guesses.

Reference: Josephus, Antiquities 18.89,237.

Other resources on line:

• Procurators - Gotthard Deutsch & Samuel Krauss cite lack of reference to Marcellus' official acts as evidence that he did not serve as governor of Judea [Jewish Encyclopedia].

• Marcellus - brief article by Jona Lendering [Livius: Articles on Ancient History].