This report surveys recent developments of carbon-neutral gas turbine combustion technology. Since the Paris Climate Agreement in 2019, each country committed a nationally determined contribution (NDC) which identifies key targets to reduce the temperature rise. In order to meet the NDC, each government is pushing hard to reduce greenhouse gas emissions, and using carbon-neutral fuel is a straightforward way to reduce to achieve the goals. As carbon-neutral fuels such as hydrogen or ammonia have different thermodynamic and transport properties, it needs paradigm changes in many related sectors. Gas turbine is one of the sectors, and this report reviews ongoing progress and challenges centered around developing carbon-neutral gas turbine combustion technology.