Really? Looking at it from one angle, he was a Jewish Rabbi, teaching a continuance of the existing religious teachings, but rejecting tradition for tradition’s sake.

Looking at it from another angle, he claimed to have always been the God people were already worshipping.

At no point did he call people to new religious practices. Everything he taught came straight out of the Tanakh, with bits from the Talmud (but mostly repudiating the Gemara portion of the Talmud in favour of stricter interpretations of the Tanakh).

The only point at which you could argue he was starting a new religion would be after his death and resurrection — at which point the main order to his disciples was still, according to the bible, to share the core truths of the Jewish teachings and religion with the rest of the world.

Christianity becoming a distinct religion happened over time between a time 50 years later and Constantine decreeing it the official religion of the Roman Empire.