While we’ve seen virus variants, we haven’t seen rapid mutation that escapes immunity and also involves greater fitness – so that the virus spreads faster and in vaccinated and previously infected populations.
This variant has multiple spike protein mutations that could help it become more transmissible and also evade immunity. Whether this variant becomes dominant or not, it’s suggestive that there are more mutations in the virus that are possible – countering prevailing wisdom that significant mutation wouldn’t be possible while continuing to infect humans.