⁃ Written informed consent;

⁃ Age ≥ 18 years;

⁃ One of the following three malignancies:

∙ Previously treated for unresectable or metastatic cutaneous or mucosal melanoma for whom no standard treatment is available (anymore);

‣ Metastatic uveal melanoma, progressing after standard of care therapy, if available;

‣ R/M HSNCC for whom no standard treatment is available anymore;

⁃ Patients must be HLA-A2\*0201 positive;

⁃ Primary tumor and/or metastasis (archival or fresh biopsy) is positive for MC2 (\>5% of tumor cells) according to immunohistochemistry;

⁃ Measurable disease according to RECIST v1.1;

⁃ At least one lesion, suitable for sequential mandatory tumor biopsies;

⁃ ECOG performance status of 0 or 1. Life expectancy ≥ 12 weeks;

⁃ Patients with melanoma must have had objective evidence of disease progression while on or after standard systemic therapy. The last dose of prior therapy (e.g. anti- PD-1, chemotherapy) must have been received more than 4 weeks prior to the start of study treatment. For melanoma patients who are treated with BRAF- and MEK inhibitors, an interval of 2 weeks between discontinuation of BRAF- and MEK inhibition and start of study treatment is sufficient;

‣ Patients with R/M HNSCC must have had objective evidence of disease progression and are ineligible for or unwilling to get platinum-based chemotherapy or for whom no standard treatment is available;

‣ Patients of both genders must be willing to practice a highly effective method of birth control during treatment and for four months after receiving the preparative regimen;

‣ Patients must meet the following laboratory values at the screening visit in the absence of growth factors and/or transfusion support:

• Hematology:

• absolute neutrophil count greater than 1.5x10\^9/L;

• platelet count greater than 75x10\^9/L;

• hemoglobin greater than 5 mmol/L or 8.0 in g/dl;

• Chemistry:

• serum ALAT/ASAT less than 3 times the upper limit of normal (ULN), unless patients have liver metastasis (\<5 times ULN);

• serum creatinine \< 1.5 ULN;

• total bilirubin ≤ 20 micromol/L, except in patients with Gilbert's Syndrome who must have a total bilirubin ≤ 50 micromol/L;

• Serology:

• seronegative for HIV antibody;

• seronegative for hepatitis B antigen, and hepatitis C antibody;

• seronegative for lues.