People always say the last two halvings caused rallies, but if you look at the timing, it's not true at all. In markets, we don't talk about "catalysts" triggering moves a year later.
In fact, shortly after the 2016 halving, price dropped by 32% over the course of a few weeks!

It would be more accurate to say Bitcoin is simply in a long term uptrend. In fact, since everyone expects upside when the halving occurs, I would expect either downside or sideways. If the crowd is heavily long, price will usually drop. Any successful trader knows the crowd is usually wrong.