Malzahar's Passive makes him too strong in lane.

As title. Malzahar's Passive gives him 90% damage reduction and crowd control immunity until 1 second after he's been engaged on.

This, combined with his safety in farming (voidlings + malefic visions), means that a good Malzahar wins every trade.

At level 6, Malzahar gets 2.5s of disable alongside %HP damage. If you start a fight and Malzahar's Passive is up (which it should almost certainly be if Malzahar's not dumb), he will get to disable you and there is nothing you can do about it, since you cannot get the initiative thanks to his passive.

Malzahar sics his Voidlings on you and ults you, and any further engagement happens with a significant health difference between you and Malzahar.

Any trade pre-6 follows the same pattern where Malzahar comes in close to spawn a Voidling and hit you with Malefic Visions prior to retreating: you are almost certainly not winning the trade since he has 1s of immense damage reduction and crowd control immunity.

It almost certainly costs any given player more resources to break Malzahar's shield than it costs Malzahar to uphold the shield, and results in a catch-22: either you spend resources and break his shield but deal virtually no damage, or you don't spend resources and Malzahar can trade with you at his leisure. In the former case, you're already down a CD, so Malzahar has more CDs than you do and is at an advantage.

Malzahar's Passive is certainly too strong and gives him too much of an edge over a great deal of laners due to immense safety built into his kit.

(To say nothing of Malzahar hard-countering any hard-engage champion simply by existing.)