More here. They are point spheres so they only take 12 seconds to render at 1080p on GPU.

Original head scan from www.3dscanstore.com. Studio HDRI from https://caveacademy.com/shop/

cell_noise.alligator -> distance.far_color -> ramp_rgb

https://help.autodesk.com/view/ARNOL/ENU/?guid=arnold_core_ac_distance_html

Original head scan from www.3dscanstore.com

https://www.artofvfx.com/the-last-of-us-vfx-breakdown-by-belofx/

Lit with a skydome_light, large area quad_light above, distant_light, and atmosphere_volume. Below you can see the difference (lighter) atmosphere_volume.diffuse (1) makes to the render.

https://sushideathrobots.github.io/

https://help.autodesk.com/view/ARNOL/ENU/?guid=arnold_core_7230_html

Original head scan model by www.3dscanstore.com