Using a pan‐IKK inhibitor BMS‐345541 (Figs 8E and EV5C and D) and a recently developed NIK inhibitor (NIKi; Mondragon et al, 2019; Figs 8F and G, and EV5E), we confirmed the implication of the NF‐κB2 pathway in MMDR, as illustrated by decreased cell cycle markers (pRb and survivin) and increased caspase‐3 cleavage, in BRAFi‐treated melanoma cells cultured on FRC‐ or MAF‐derived ECMs. Here, RB1 is linked to melanoma.