Yes, Nivolumab can cause skin rashes or hives. According to the drug's official patient information, some of the most common side effects of Nivolumab include skin rash and itching [1]. These skin reactions are typically mild to moderate; however, in rare cases, they can be severe or life-threatening.

Nivolumab is a type of medication known as an immune checkpoint inhibitor, which works by helping the body's immune system to fight against cancer cells [2]. However, this mechanism of action can also lead to the immune system attacking healthy cells, causing a range of side effects, including skin reactions.

If you experience a skin rash or hives after taking Nivolumab, it is essential to inform your healthcare provider immediately. They may recommend treatment to alleviate the symptoms or, in severe cases, may need to adjust your medication or provide additional therapies to manage the side effects.

In summary, Nivolumab can cause skin rashes or hives, and it is crucial to monitor for and report any skin reactions to your healthcare provider.

Sources:
[1] "Nivolumab (Opdivo) Injection, for Intravenous Use: Side Effects, Interactions, Warning, Dosage & Uses." RxList, RxList, 12 Jan. 2022, <https://www.rxlist.com/nivolumab-opdivo-drug.htm#side_effects>.
[2] "Nivolumab." DrugPatentWatch, DrugPatentWatch, 12 Jan. 2022, <https://www.drugpatentwatch.com/drugs/nivolumab>.