Mission related combat content scales with the combat rank rating of the mission you accepted among other factors. Some of these can be achieved by interdicting a target ship or by failing/submitting an interdiction, or as a random encounter.
Target is a randomly selected pirate ship as would be found in a HazRES. Can have few wingmen. Difficulty: Low - Medium, scales with mission.
Multiple mission targets. Difficulty: Low - Medium, scales with mission.
Mission target in either an engineered Fer-de-Lance, Python or Conda/Corvette/Cutter. Escorted by 2-3 engineered Vultures. Difficulty: Very High
Multiple mission targets. Spawn at Threat Levels 3 - 4. Threat 4 guarantees a scenario where you will have to tank multiple ships at once. Difficulty: High