Group 1: Participants with non-small cell lung cancer (NSCLC) as per inclusion/exclusion criteria undergo baseline PD-L1 expression testing by immunohistochemistry and [99m-Tc]-anti-PD-L1 single-domain antibody SPECT/CT imaging at 0 and 9 weeks.

FDG-PET/CT is also performed at baseline (0) and first follow-up (9) weeks scans, in addition to standard CT clinical imaging at 0, 9 and 18 weeks.

Group 2: Participants with malignant melanoma (MM) as per inclusion/exclusion criteria undergo baseline PD-L1 expression testing by immunohistochemistry and [99m-Tc]-anti-PD-L1 single-domain antibody SPECT/CT imaging at 0 and 12 weeks.

FDG-PET/CT is also performed as standard clinical imaging at baseline (0), first follow-up (12) weeks and 24 weeks.

Technetium labelled anti-PD-L1 single-domain antibody (NM-01) single-photon emission computed tomography (SPECT)/CT

PD-L1 expression reported by measurement of tumour:blood pool ratio and/or SUV of [99mTc]-anti-PD-L1-sdAb uptake on SPECT. Measurement at baseline and 9 weeks will be compared to determine % change.

Standard clinical imaging assessment at 9 and 18 weeks used as comparators.

PD-L1 expression reported by measurement of tumour:blood pool ratio and/or SUV of [99mTc]-anti-PD-L1-sdAb uptake on SPECT. Measurement at baseline and 12 weeks will be compared to determine % change.

Standard clinical imaging assessment at 12 and 24 weeks used as comparators.

Correlation between PD-L1 expression reported by measurement of tumour:blood pool ratio and/or SUV of [99mTc]-anti-PD-L1-sdAb uptake on SPECT and PD-L1 expression determined by standard of care immunohistochemistry.