Not as a true, exact depth-of-field overlay. In practice, the closest feature is focus peaking, which many mirrorless cameras offer in the EVF and rear LCD. It highlights edges that appear acceptably sharp, and on some cameras this changes roughly with aperture, so it can give a practical sense of the near/far sharp range. Fuji models such as the X-T3 and X-Pro2 were mentioned as examples.

But a camera generally cannot know exact final depth of field for every part of the image. Apparent DoF depends on the final display size, viewing distance, and the viewer’s visual acuity, all of which are unknown at capture time. Also, a single-lens camera usually does not have full per-pixel scene distance information; phase-detect AF only provides limited focus-distance information, not a complete depth map.

So: yes, many mirrorless cameras can approximate this with focus peaking, but no, they do not provide a precise “within DoF” overlay in the strict sense.