Why does chrome render different unicode characters ””(U+2F804)”和你”(U+4F60) are the same characters

A note: unicode code point and font glyphs are not directly related. The actual glyph depends on context, ligature, combining characters, language, and possibly other factors (see Unicode standard).

Unicode defines that U+2F804 is decomposable to U+4F60. Often Unicode texts are normalized by software. Either by decomposing them (so often splitting characters and accents e.g. for Latin languages), or by composing them. Such algorithms are described in Unicode. So in that case, it is considered U+4F60 semantically fully equal to U+2F804 (and preferred form). It is not frequent to see decomposition which contain the same number of code points (but also not unseen). And it is also not seldom to have decomposition in one direction, and no relation on the other direction.

This character is in CJK Compatibility Ideographs Supplement, so the important part is compatibility, and this is confirmed also by wikipedia article (https://en.wikipedia.org/wiki/CJK_Compatibility_Ideographs_Supplement).

Compatibility codepoint were introduced to simplify introduction of Unicode, by providing a lossless roundtrip conversion of other encoding. [In such manner, one could implement Unicode on different layers, without problems and fully transparent, and without requiring to change other layers (or worse: to change all stack in one step).