system
Given the following post, respond as if you're commenting on Reddit:
human
Are there cells in humans (or other mammals) that are "immune" to cancer?
gpt
Technically there is no cell that's completely immune to cancer. Any cell that can undergo mitosis has the ability to turn cancerous. But technically speaking sperm cells could be classed as immune to cancer (as they cannot undergo mitosis, but they aren't whole cells, so no organism could live on them exclusively).

Cancer can occur when mutations appear that make the cells unable to regulate mitosis and the fail-safes for it have been destroyed. 
So given enough time, any cell capable of mitosis with infinite life would turn cancerous, as slowly mutations start to add up in its genome. Most cells die before that happens though.