That extensive list for Keytruda and other checkpoint inhibitors is because they disregulate the immune system causing an autoimmune response. Leronlimab on the other hand brings a disregulated immune system into balance.
Let's look at Keytruda's inhibition of PD-L1. PD-L1 and it's chemokine PD-1 keep the immune system from attacking healthy cells when they bind. Tumor cells elevate PD-L1 and PD-1 to keep themselves safe from destruction. But Keytruda completely blocks PD-L1 on both tumor cells and healthy cells allowing the immune system to attack healthy cells.
But why doesn't leronlimab do the same by downregulating PD-1? The key word here is downregulation (not complete blockage as with Keytruda). Other CCR receptors bind the same chemokines as CCR5 but to a lesser extent. But those other receptors are still elevated from normal in the case of cancer and other diseases. Combined with CCR5 there's an overactive immune system. Blocking CCR5 still allows the other elevated chemokines to operate but brings things down to a normal level. That allows the PD-1/PD-L1 action to still exist but not to the same extent in tumors.
Most immune effective drugs completely take down a specific link in the immune system causing problems. Leronlimab is broadly acting on the immune system but operates in a golden space that still allows the immune system to function properly. Something the FDA does not understand at all, thus the 2 doses in our Covid trials.