Do pandemic border closures violate Article 43 of the International Health Regulations? (very hot topic in public international law because of COVID-19)
OR
What is the legal basis for diplomatic asylum? (also very popular because of the Julian Assange case)
This appears to be a philosophical question. In every set of rules, there are circumstances to be considered when applying these rules. This is because life is not mechanical but intertwined and interlocked and interlinked and interconnected (to say the same thing in more than one way). Life and riles do not interact in mutually exclusive settings. That is why even in courts of law, after the facts and the law have been established, mitigation and aggravating circumstances are considered - sometimes with evidence and arguments to anchor and prove them too. Thus also explains why the law of "though shalt not kill" in most status of the civilised world, end up differentiating killing into subsets like murder, suicide, homicide, manslaughter, and never mere killing.
It is a vast field of study. One may consider the following points to begin with;
1. The incorporation of ICL/IHL objectives within domestic law. Including a discussion on different approaches towards substantive and procedural safeguards, power and jurisdiction of domestic courts...
2. Support and involvement of States in the international processes. Including membership and cooperation with ICC.
3. Study of concepts which are exclusive to the subject. E.g. universal jurisdiction, jus cogens, erga omnes, humanity.
4. Study concepts which overlap with existing penal jurisprudence of systems. E.g. mens rea, circumstantial evidence, witness testimony and conspiracy.
5. The various reforms being advocated for strengthening the existing frameworks. E.g. inclusion of ecocide as a crime against humanity...