ACTB and Miyoshi myopathy: To define metastasis‐specific CAF profiles by scRNA sequencing, we applied the MT‐ret melanoma fragment transplantation model (Gengenbacher et al. 2021) (MT‐ret–derived model) and combined it with mT/mG mice (Gt (ROSA)26Sortm4(ACTB‐tdTomato,‐EGFP)Luo/J) (Muzumdar et al. 2007), generating MM primary tumor samples and corresponding lung metastases, in which engrafted tumor cells are unlabeled while host TME cells constitutively express tdTomato (Figure S1a).