There is sun, which is slightly yellowish (or orange to red at sunset), and there is sky light which is obviously bluish. Sun is directional, sky light is not. Sun is a light source far away, but sky is a light source all around the scene.
The rest, well, can be done with a lot of bouncing, refraction, diffusion subsurface scattering, etc.
[0] The classic is Naty Hoffman's 2002 work on atmospheric scattering http://developer.amd.com/wordpress/media/2012/10/GDC_02_Hoff... , but it has been developed over the years, e.g. Sebastian Hillaire's work on both Frostbite https://media.contentapi.ea.com/content/dam/eacom/frostbite/... and Unreal Engine https://blog.selfshadow.com/publications/s2020-shading-cours...
In all realistic rendering software, skylight and sun (or other celestial bodies, like Moon) are modeled as separate sources of light, with different light characteristics.
The sun light is white during the day, otherwise, anything white would appear yellow.
As I said, human vision has a kind of adaptive white balance that cancels out peaks like this to some extent. It also does that for artificial light sources with uneven spectra (neon light, blueish white LED lights...). [Side note: this is also the reason why cameras have adjustable white balance. A picture taken by a neutral sensor under some artificial lights is perfectly correct, but looks color tinted and wrong to the human eye afterwards, because the eye under the same conditions has a shifted white point.]
Why is this important? If you set up a light source in a renderer, you often get a pretty naive equal energy white as a default, which is simply not what you need for sunlight, even at noon under a clear sky.
If the sun color was actually yellow, people wouldn't be able to tell the difference between a white object and yellow object under the sun light (they would both appear yellow). And clearly they are.
On the other hand a white object doesn't get any "whiter" under another kind of light than it appears under direct sun light, this again is because the sun light is white, and not yellow.
Of course there is some subjectivity here, but it is a misconception to call the sun light yellow. For example, this "bright sun" RGB [1] color, is clearly not the color of direct sun light. Hopefully, you will agree with this.
A yellow object and a white object would be not discernible under a very narrow-band yellow light, or a mix of two narrow-band red and green lights of right proportions. This is how LEDs and lasers emit light, but totally unlike hot objects (like Sun) or fluorescent lamps (like "natural light" LED lamps) emit light.
It has to be because white was historically described as the color of the snow (or whatever is white) under the sunlight.
Now, if you want to adopt a more precise definition of white and other colors, based on (not so) recent scientific insights about the light, you can. Then the sunlight is not white, neither is snow or sugar. And is also certainly not yellow.
Let's be honest, the sun light is almost perfectly white, and kids use yellow to draw the sun, because it wouldn't make sense to draw it with white.
The eye has a built-in white balance correction, and it moves the white point towards longer waves as the brightness lowers. This is why a single 5600K lamp in a room makes bluish light, while 10 of the same lamps make it lit by bright white. Same, a single 2500K lamp in a room makes a calming sort-of-white light. but 10 such lamps make a unmistakably yellow light.
The sunlight outside at a cloudless summer noon is very bright (one usually even wants to wear sunglasses), so the sun looks white or yellowish, especially in contrast to the blue sky.