Keywords: 2-hit mechanism; PD-1 inhibitors; PIRME; Stevens-Johnson syndrome; atypical presentation timeline; cancer care; cutaneous toxicity; delayed developmental timeline; delayed onset; immune checkpoint inhibitors; immune-related adverse event; immunotherapy; oncodermatologist; oncodermatology; pembrolizumab; pembrolizumab-induced; progressive immunotherapy-related mucocutaneous eruption; toxic epidermal necrolysis; toxicity.