• Tumor type

• For dose escalation and back fill and dose optimization (Parts A and B):

‣ Participants with a histologically confirmed lymphoid neoplasm who in the judgement of the investigator have no appropriate standard therapy available at the time of enrollment and are a candidate for PF-08046044/SGN- 35C treatment. Eligible subtypes and treatment status are as follows:

• Participants with relapsed/refractory (R/R) cHL: should have received at least 3 prior systemic therapies including autologous stem cell transplant \[ASCT\] (ASCT and the associated high-dose chemotherapy prior to ASCT are considered to be 1 prior line, along with post-transplant consolidation if progression has not occurred between transplant and start of consolidation) or an anti-PD-1 agent (or refused/were ineligible); or 2 prior systemic therapies if, according to the investigator, no other appropriate standard treatment is available.

∙ Participants with R/R PTCL (excluding systematic anaplastic large cell lymphoma \[sALCL\]): should have received at least 2 prior systemic therapies, or 1 prior systemic therapy if, according to the investigator, no other appropriate standard treatment is available.

∙ Participants with R/R sALCL: should have received at least 2 prior systemic therapies, including 1 brentuximab vedotin-containing regimen, or 1 prior line of systemic therapy including brentuximab vedotin, cyclophosphamide, doxorubicin, and prednisone.

∙ Participants with R/R DLBCL: should have received at least 2 prior systemic therapies, including ASCT and chimeric antigen receptor (CAR) T-cell therapy, or were ineligible, or refused.

⁃ Participants with PTCL and DLBCL must have a detectable cluster of differentiation 30 (CD30) expression level (≥1%) in tumor tissue from the most recent biopsy obtained at or after relapse by local testing.

• For dose expansion (Part C):

‣ Participants are eligible irrespective of CD30 expression on tumor tissue; however, participants must provide tumor tissue for evaluation of CD30 expression from the most recent biopsy obtained at or after relapse.

⁃ Participants with cHL, PTCL, sALCL, and DLBCL: Eligible subtypes are the same as defined in Parts A and B

⁃ If activated, the biology cohort may enroll the populations included in Parts A, B, and C.

• Eastern Cooperative Oncology Group (ECOG) Performance Status score of ≤1

• Fluorodeoxyglucose positron emission tomography (FDG-PET) avid and bidimensional measurable disease as documented by radiographic technique (spiral computed tomography \[CT\] preferred)