I once got to meet a Tasmanian Devil baby at a zoo. The zookeeper was carrying him around in a little pouch to keep him comfy while his mom was getting a vet checkup. (The picture is one I found on google because the picture I took is buried in some backup folder from about 6 phones ago)
A lot of “tumors” seen on wild animals are fungal infections from invasive fungal species brought by humans. It really sucks because fungal infections are very hard for mammalian immune systems to fight without help from antifungal medications.