Resolves to Yes if any party uses a chemical or biological weapon on any target military or civilian, within Israel or Palestine, by the end of the year. If an attack is ambiguous, we will wait until both CNN and Al Jazeera declare that some kind of chemical attack took place, regardless of its perpetrators. If such weapons are not discovered, or are discovered but not used, this resolves No. Weapons that are only technically chemical (such as explosives) or biological (such as waste water) will not count; please accept the spirit of the question.

Israel is suspected to have ongoing chemical and biological weapons programs: https://en.wikipedia.org/wiki/Israel_and_weapons_of_mass_destruction#Chemical_weapons

Hamas has been accused of carrying around chemical weapon manufacturing instructions during terrorist attacks: https://vxtwitter.com/SkyNews/status/1716176823862587814