ITV (the broadcaster) has never released full series of the show on Blu-ray or DVD. Instead, episodes are available for streaming on (in the UK) and selected seasons on platforms like Netflix or Amazon Prime Video depending on your region.
There is currently of I’m a Celebrity… Get Me Out of Here! UK Season 21 (2021). i'm a celebrity... get me out of here uk season 21 bluray
If you’re looking for physical media, you may occasionally find unofficial or region-specific compilation DVDs (e.g., “Best Moments”), but not a complete season 21 Blu-ray. ITV (the broadcaster) has never released full series