High-resolution georeferenced population data
For "historical" population data, you can refer to the Gridded Population of the World (GPW), version 4. This dataset makes available estimates of population at ~1 km resolution (30 arc second) for the years 2000, 2005, 2010, 2015, 2020.

The GPWv4 was also used by the European Commission's Joint Research Centre for the Global Human Settlement project. This dataset makes available residential population estimates for target years 1975, 1990, 2000 and 2015 at 250m and 1km spatial resolution.

If you also need future projections, you can refer to the Shared Socioeconomic Pathways (SSP) scenarios downscaled by Murakami and Yamagata (2019), available here, or by Jones and O'Neill (2016), made available through the ISIMIP project portal.