Inclusion Criteria:  Subjects will be eligible for enrollment in the study if they meet ONE criteria a, b or c in point 1 and ALL the criteria in points 2-9.  Subjects must meet ONE of the criteria a, b or c below:  For enrollment into Cohort A: Subjects with histologically confirmed advanced or metastatic non-uveal/non-mucosal melanoma or merkel cell carcinoma (MCPyV positive and negative) who are not amenable to surgical cure and are candidates to receive single- or combined IOT alone (not to include cytotoxic chemotherapy) as first line treatment. For enrollment into Cohort B: Subjects with histologically confirmed advanced or metastatic nonpapillary Renal Cell Carcinoma who are not amenable to surgical cure and are candidates to receive single- or combined IOT alone or IOT in combination with tyrosine kinase inhibitor (not to include cytotoxic chemotherapy) as first or second line treatment. For enrollment into Cohort C: Subjects with histologically confirmed advanced or metastatic non-small cell lung cancer without non-smokers/driver mutations who are not amenable to surgical cure and are candidates to receive Atezolizumab as a monotherapy for first line treatment.  Subjects must meet All of the criteria 2-9 below:  At least 1 RECIST 1.1-measurable. non-irradiated, non-cutaneous, non-osseous (unless there is an associated measurable soft-tissue component) lesion documented on intravenous (IV) contrast-enhanced CT or MRI (per RECIST criteria 1.1) prior to first 89Zr-Df-crefmirlimab infusion. Has an adequate washout period before the date of consent as defined by: Eastern Cooperative Oncology Group (ECOG) performance status ≤2 and anticipated survival of at least 6 months. Subject must be IOT naïve. Meeting all clinical safety lab values per institution's SOC, or investigator's discretion, for subjects receiving cancer treatment. Male or female age ≥18 years. Ability to understand the purposes and risks of the trial and has signed an Institutional Review Board (IRB) approved informed consent form. Willingness and ability to comply with all protocol required procedures. For men and women of child-producing potential, use of effective double barrier contraceptive methods during the study, up to 30 days after the last administration of the investigational product.  Exclusion Criteria:  Subjects will NOT be eligible for enrollment in the study if they meet ANY of the following criteria:  Bone-only disease on conventional imaging (MRI, PET, CT) or skin- only lesions. Serious nonmalignant disease or conditions that in the opinion of the investigator and/or ImaginAb could compromise protocol objectives. Subjects with splenic dysfunction or who are status post splenectomy will be discussed on a case-by-case basis due to the importance of the spleen in CD8 imaging as a reference tissue. Pregnant women or nursing mothers.