Why Couldn’t Palpatine Find Yoda After Order 66?
Despite doing everything in his power to hunt down and slaughter all remaining survivors of Order 66, including creating the order of the inquisitorius, one Major Name managed to avoid DArth Sidious’ radar. That was Grandmaster Yoda.

Because of this, Palpatine searched tirelessly for the Jedi Master but simply could not locate him despite his best efforts. So why was this?

The dark side cave on Dagobah was actually able to mask Yoda’s presence on the swamply world, and anyone who searched there with the force would simply see a chaotic and fuzzy mess of life. So in a way, the planet itself having a strong affinity to the force protected Yoda’s presence there and allowed Luke Skywalker to be trained and later redeem his father.