What pair of chromosome doesn't go through crossover or recombination?

The pair of chromosomes that doesn't typically undergo crossover or recombination is the sex chromosomes in many organisms, particularly in humans, where the X and Y chromosomes are involved. During male meiOSis, the X and Y chromosomes can pair but often do not exchange genetic material, especially in regions called the pseudoautosomal regions (PARs). This lack of recombination helps maintain the distinct characteristics of the sex chromosomes across generations.