Nobody can answer this question in my opinion because Cryptocurrency has a global market which means any news around the world could dominate the new trend.
At present, there are many positive news spreading in the market like a wildfire. News such as Facebook's Libra coin, the upcoming halving, US vs China money game etc.. are in trend and dominating the crypto market.
So we can't say whats exactly boosting the bull market. We should just be happy that the long bear market is finally over (though it has been time since the bear market was over).