BRAF and metastatic melanoma: Among the various metastatic melanoma cell lines (Figure S2, Supporting Information), we printed the monospheroids made of SK‐MEL‐28, a human malignant melanoma cell line expressing BRAF(V600E) mutated form, due to their high invasiveness and high suitability for studying metastatic melanoma.[7, 18] The heterospheroids were synthesized by integrating the human dermal fibroblasts, which play a predominant role in melanoma progression.