Trying to "rescue" this image (and others?), the links provided in some of the above responses may be very helpful.
But it would always be better to prevent the problem than to have to correct it later in post-processing (as shown at the links above).
According to the image EXIF, that was shot with a Sony A7 III, ISO 1250, 1/800 shutter speed and f/2.8 aperture (Sony FE 70-200mm f/2.8 GM OSS lens at 136mm focal length)...
I suspect it's the lighting that is causing this effect in the image. I've seen similar "banding" in LED lighting, in particular. If that's the case, a different shutter speed might have helped. Some cameras have means of "tuning" the shutter speed more precisely to match the lighting. I don't know the A7 III camera, so can't say what's possible with it.
Here it also might have something to do with using "silent" mode. I think that means the electronic shutter was used. It may have been better to use the mechanical shutter, but I really am not really sure. With many cameras, it does prevent the "rolling shutter effect" to use the mechanical shutter instead of the e-shutter. This "banding" caused by the lighting may be related to rolling shutter and solved in the same way.
I don't know if an A7 III has "Flicker Free" or "Anti-Flicker" mode like many Canon and some Nikon do... However I don't believe that would have solved this problem anyway. What that feature does is solve overall exposure problems caused by cycling lights, such as fluorescent, sodium vapor, etc. Those types of lights actually cycle on and off very rapidly. Our eyes don't see it, but our cameras sure do! Flicker Free/Anti-Flicker detects the cycle and times the shutter release to the peak output of the lights. It's a great feature.
The only way to minimize exposure issues under those types of lights without this feature is to use a slower shutter speed that makes it more likely you'll capture the peak light output (or use a flash, to take the ambient lighting out of the equation). The off/on cycle of those lights in the US is 60 hertz, in Europe and some other parts of the world, it's 50 hertz. So using a 1/30 or 1/15 shutter speed can help... but isn't foolproof, can make for problems hand holding a steady shot, and just isn't fast enough for most moving subjects.
Flicker Free/Anti-Flicker works much better and allows a faster shutter speed that will make hand held shots possible as well as freeze subject movement. Canon's version auto detects the rate of the cycle. Nikon has it on fewer cameras, where it also can auto detect the rate, but also allows the user to manually select the 50hz or 60hz setting. I've used this feature a lot on my Canon cameras and it's a real game changer shooting sports where a fast shutter speed is necessary. In the past, without Anti-Flicker I had to take lots of extra shots because it was a good bet that around half of my images would be seriously under-exposed. Some would be recoverable in post-processing, but a lot of shots would be ruined. Now using newer cameras with Anti-Flicker I see very, very few exposure problems when shooting "under the lights". There is a more detailed description of Canon's Anti-Flicker, with example images, here: https://www.the-digital-picture.com/Canon-Cameras/Anti-Flicker-Mode.aspx
But, once again, I don't don't know if that Sony camera has the Flicker Free/Anti-Flicker feature... And it wouldn't solve this particular problem anyway.
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Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2), EOS M5, some other cameras, various lenses & accessories
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